can power conditioners cause lcd displays to function free sample

The HD Guru’s readers have asked for the real story on power line conditioners. Are they really needed with an HDTV? Do they provide a sharper picture as some salesmen claim? How well do they protect the TV in case of a lightening strike or other electrical spike? What about surge protectors and uninterruptible power supplies (UPS)? The HD Guru responds.

In the United States the alternating current (AC) sent from your electric company should be delivered to your home at a steady rate of 120 volts at 60 cycles per second. In some parts of the US, there are variations, resulting in voltages that are either too high or too low. Sometimes interruptions cut the power altogether. Delivery of too much power is called a voltage surge; too little, a voltage droop or sag. Electrical storms can deliver lightening strikes, which can produce catastrophic voltage surges capable of destroying the power supplies of all the electronics plugged into the system, whether they’re powered up or not. Air conditioner and refrigerator motors powering on and off can also cause momentary voltage fluctuations. Another potential power problem is electrical interference caused by industrial grade electrical equipment operating nearby as would be found in a factory. Your home’s wiring may also pick up electrical line interference or radio frequency interference (RFI) caused by, among other things, broadcast transmitters located in your vicinity.

Fluctuating voltages can cause lights to brighten and dim. TV, lights and other electrical devices may momentarily shut off due to total voltage dropouts. Radio frequency interference can create hum and/or video noise bars and static.

Power conditioners can’t give your digital HDTV a sharper picture or better color, regardless of display technology, whether plasma, LCD, DLP, SXRD, or DILA rear projection. Period. Resolution is, by definition fixed, and so cannot be increased. If a salesman tells you otherwise, ask why are there no power conditioners connected to the dozens of TVs on display. All HDTVs have internal power supplies designed to filter and transform the incoming AC to voltages necessary for the set’s operational needs. These built-in power supplies do a great job, and are designed to accept a fairly wide range of line voltages. Can a power conditioner clean up heavy interference in your power line? Yes, but most of the time they are simply not necessary and will be of no use because the vast majority of households are free of electrical interference.

While power conditioners cannot improve your picture, a surge protector can protect your set in the event of a power surge. What’s needed depends on the display and the amount of protection you can afford. For LCDs and plasmas the HD Guru suggests a surge protector at the very minimum. According to experts, the rating should be at least 360 joules. These are very inexpensive, with prices starting at under $20. For lamp driven devices such as microdisplay front and rear projectors, including LCOS (Sony SXRD and JVC DiLA), DLP and LCD, you should purchase an uninterruptible power supplies (UPS). The HD Guru also recommends using the UPS with digital video recorders (DVRs like TiVo). A UPS will prevent the lamp’s cooling fan motor (or hard drive in the DVR) from shutting off during a power failure. You need just enough battery power to cool off the projector to prevent premature lamp failure or a DVR’s power down. 10 minutes worth of battery back up is more than sufficient. Virtually all UPS units also have built-in surge protection.

UPSs’ are either on-line or off-line designs. The on-lines are best because they actively filter and convert AC wall power into DC (Direct Current) to charge the battery, while simultaneously converting the DC back to AC to run your HDTV or DVR. In addition to offering excellent line conditioning, on-line UPS systems provide surge protection. Because it’s “on-line” there is no voltage drop when the AC power fails. The switch to battery backup is seamless.

The Tripp-Lite SU750XL is a good on-line UPS. Rated at 750VA, it will run a 500-watt load for about 10 minutes, which is plenty of time to cool off the lamp in any projector or properly shut down a TiVo. While it retails for $449, a quick internet search found it for $288.93 + shipping.

Depending upon capacity off-line UPS prices start at around $40. Because the AC in/out circuitry is not coupled to the output there’s around a 1-millisecond switch between line current and battery power. Virtually all have built-in surge protection and many of the mid size and larger one also have line conditioners.

Bottom line? Instead of selecting a line conditioner with surge protection, which can cost up to $500 or more, get first-rate protection that includes surge and battery backup plus top quality line conditioning, for under $300 by purchasing an on-line UPS. For under $100 you can be protected from the most common surge and short-term power loss problems with a UPS with surge protection combo.

While working on my recordings for my eLearning podcasts, I constantly tried many different ways to improve the quality of my recordings as well as give my equipment the best care.

One of the ways I tried to do this was testing out both power conditioners (also known as line conditioners) and surge protectors. Therefore, I thought it would be a good idea to pass on my learned knowledge to others through this article.

Below, I will explain what a power conditioner is, why you may need one, the main differences between power conditioners vs surge protectors, and help you decide which one to choose for you and your needs.

After many years of experience using these tools as well as conducting lots of research, my goal is to help others out by saving them countless hours of searching for information and providing the knowledge that I have learned.

A power conditioner, also commonly referred to as a line conditioner, is a neat device that was created to improve the overall quality of the power that is going to your electrical equipment.

When the power goes through your home’s electrical system, it needs to travel to your everyday appliances, such as a refrigerator or an air conditioner.

When this happens, you may experience disturbances in your appliances. For example, your lights may flicker or the picture may look distorted on your television.

Most people who experience these situations typically ignore them, which may cause your appliances to work harder than needed. If this happens, they may wear out a lot quicker than expected and need to be replaced more often.

This is useful because it provides the correct voltage level to sensitive electrical equipment, which increases your appliances’ ability to work efficiently and safely at the proper voltage.

A line conditioner will come in and clean up your power, helping it run more effectively. If you would like to ensure that your appliances are reaching the correct voltage, my advice is to purchase a line conditioner.

This device not only helps my podcasts by ensuring that the power reaching my recording devices are the proper voltage limit that it was designed to run at, but a line conditioner also offers excellent filtering.

However, I learned that this was not the case. I then purchased a great power conditioner, which began improving the sound quality of my analog and digital gear as well as extending its life. Now, I cannot imagine ever going without this device.

If you would like more details on the line conditioner and its functions, check out Sweetwater’s YouTube video. In this video, Mitch Gallagher explains what a line conditioner is as well as its many benefits.

A surge protector, sometimes called a surge suppressor, is a device that protects electrical devices from voltage spikes and increases in alternating current circuits.

When a voltage spike occurs, such as during lightning strikes that lead to power surges or even power outages, it can destroy your electronics that are plugged in, such as audio equipment, computers, televisions, modems, and so much more.

The majority of surge protectors send the electrical current from the wall outlet to all of your electronic devices that are plugged into its power strip. If the voltage starts to surge, this neat device will divert the extra power supply to the outlet’s grounding wire.

One of the most important components of surge protection is the Metal Oxide Varistor (MOV), which is responsible for diverting the extra voltage. The MOV can easily burn out with one voltage spike. Therefore, I recommend purchasing a surge protector that is equipped with a light that lets you know if the device is working properly.

Additionally, an important term that you should remember is “clamping voltage.” This term is the maximum amount of power that can go through a surge protector before it restricts further voltage from going to an electrical device or computer. It is very important that you check the clamping voltage when searching for the perfect surge protector. By doing this, your surge protection will last longer as well as protect your gadgets from larger voltage spikes and power surges.

In my opinion, the risk is not worth it, and you should only look at surge protectors with at least a 600 or higher voltage limit. Most computers come with their own clamping voltage, but once that voltage limit is surpassed, the computer will experience damage.

Knowing the clamping voltage and purchasing an excellent surge protector will help ensure that your computer or any other electronic gadget does not experience a higher voltage level than it can handle.

If you are a person who has a lot of devices plugged in like myself, my advice would be to consider buying a surge protector. While recording podcasts, I use a lot of different electronic devices, and I have invested a lot of money into my gear that I use every day. Therefore, I have learned to use a surge protector to protect my equipment and home from any potential voltage surges.

For a brief video on surge protectors and how they work, consider taking a look at GalcoTV’s YouTube video. This video is very informational as Katie Nyberg elaborates on the several duties that a surge protector is responsible for.

If you are interested in watching a more in-depth video explaining the various functions of the surge protector, I suggest watching Techquickie’s YouTube video. This video will teach you all that you need to know about surge protectors in less than six minutes.

A line conditioner and surge protector may seem similar. However, there are several key differences to look at when it comes to these two separate devices. I will point out a few of these differences below.

A line conditioner uses its elements to eliminate any possible damages to electronic gadgets, such as system destructions, operation disruptions, or component degradations.

If you are looking for a way to protect your equipment or electric appliances, line conditioners/power conditioners and surge protectors are both great options to look at. This can be a difficult decision that must be decided based on your overall needs.

My advice is to choose a line conditioner if you are looking to protect equipment that is very important to you. Big businesses use line conditioners to protect their equipment from electric shocks. Therefore, your smaller home studio or office will most likely do really well with a line conditioner.

For someone looking for a cheaper option to the power conditioner, I suggest purchasing a surge protector. This will keep high voltage from being transmitted to your plugged-in electronics. It will also prevent any damages to your equipment.

The only thing that you must keep in mind is that you will need to replace your surge protector every so often, which means this could seem like the cheaper option in the beginning but may end up being more expensive in the long-run than a power conditioner.

Some people choose to use both of these unique devices to give an extra layer of protection. By doing this, you will also give yourself some relief knowing that you are doing all that you can for your electronic gadgets and devices.

I hope that this article was successful in teaching you what a power conditioner is, what a surge protector is, and their main differences. I hope it also was effective in helping you decide which one or if both may work for you and your needs. As a professional who records multiple podcasts a week, both of these devices are essential to my daily needs.

However, you may feel that one has more benefits than the other when it comes to your work. Regardless of what you decide, always do what is best for your equipment.

Hi, I’m Scott Winstead, an e-Learning technology geek with 20 years of experience. Follow this blog for opinions on blended learning and flipped classroom techniques, reviews of home studio equipment, and tips for voice-over actors and digital audio content makers, technology how-tos, and more!

Analog signals need to be correctly "prepared" before they can be converted into digital form for further processing. Signal conditioning is an electronic circuit that manipulates a signal in a way that prepares it for the next stage of processing. Many data acquisition applications involve environmental or mechanical measurement from sensors, such as temperature and vibration. These sensors require signal conditioning before a data acquisition device can effectively and accurately measure the signal.

For example, thermocouple signals have very small voltage levels that must be amplified before they can be digitized. Other sensors, such as resistance temperature detectors (RTDs), accelerometers, and strain gauges require excitation to operate. All of these preparation technologies are forms of signal conditioning.

Signal conditioning is one of the fundamental building blocks of modern data acquisition(aka DAS or DAQ system). The basic purpose of a data acquisition system is to make physical measurements. They are comprised of the following basic components:

Data acquisition systems need to connect to a wide variety of sensors and signals in order to do their job. Signal conditioners take the analog signal from the sensor, manipulate it, and send it to the ADC (analog-to-digital converter) subsystem to be digitized for further processing (usually by computer software).

As the name implies, they are in the business of conditioning signals so that they can be converted into the digital domain by the A/D subsystem, and then displayed, stored, and analyzed.

After all, you cannot directly connect 500V to one of the inputs of an A/D card - and thermocouples, RTDs, LVDTs, and other sensors require conditioning to operate and to provide a normalized voltage output that can be input into the A/D card.

In the world of electric sensors, we need different types of signal conditioning circuits in order to properly condition signals coming out from those sensors. Today common types of signal conditioners are:

The best signal conditioners provide electrical isolation between the inputs and their outputs. Isolation reduces noise, prevents ground loops in the measuring chain, and ensures accurate measurements.

Sometimes also referred to as galvanic isolation, electrical isolation is the separation of a circuit from other sources of electrical potential. This is especially important with measuring systems because most signals exist at relatively low levels, and external electrical potentials can influence the signal greatly, resulting in wrong readings. Interfering potentials can be both AC and DC in nature.

For example, when a sensor is placed directly on an article under test, (e.g. a power supply) which has potential above ground (i.e., not at 0V), this can impose a DC offseton the signal of hundreds of volts. Electrical interference or noise can also take the form of AC signals created by other electrical components in the signal path or in the environment around the test. For example, fluorescent lights in the room can radiate 400 Hz which can be picked up by very sensitive sensors.

This is why the best data acquisition systems have isolated inputs - to preserve the integrity of the signal chain and ensure that what the sensor outputs is truly what has been read. There are several kinds of isolation techniques employed today.

It is important that isolation is in place not just from channel to ground, but also from channel to channel. Excitation lines should also be isolated where necessary. A comprehensive isolation system prevents damage to the systems from excessive voltage and avoids ground loops and wrong measurements.

As one example, signal conditioners of Dewesoft’s SIRIUS DAQ systems provide isolation of 1000V (the HV high voltage module is additionally rated CAT II 1000V).

The best signal conditioners are fully adapted to the sensors that they are intended to be used with. At the most basic level, this includes the use of the appropriate connector(s) for these sensors.

Voltages are typically handled with BNC connectors (up to 50V), and safety type banana plugs above that. For voltage output sensors that require sensor supply by the signal conditioner, a multi-pin connector is used, such as compact and high-reliability LEMO connectors, or less-expensive (but larger) DB9 (DSUB-9) connectors. This is why most manufacturers, Dewesoft included, make their voltage signal conditioners available with a variety of connector types.

Strain gauges are usually sold with bare wires because there is no industry standard for the multi-pin connectors that should be used, or for the wiring method that the engineer will choose (3-wire, 4-wire, sense lines or no sense lines, etc). The most commonly employed multi-pin connectors used in strain gage applications are compact and high-reliability LEMO connectors or less-expensive (but larger) DB9 (DSUB-9) connectors.

It should be mentioned that for data acquisition systems that are permanently mounted in an industrial measurement environment, these requirements are different. Unlike a typical data acquisition system that is going to be moved around and used for a variety of applications, these systems are “fixed” and do not change. Fixed or embedded systems are typically outfitted with screw terminal block connectors, which are very efficient and low-cost. They do not have to be rugged or tamper-proof since they are locked away.

The ability to select the proper measuring range for a given sensor is the most basic essential function of a signal conditioner. In order to get the best possible results from their measurements, engineers must be able to set the voltage level (or gain in general) of the conditioner.

For example, if you are trying to measure a voltage that spans from ±2.5mV (±0.0025V), but your conditioner only has a ±50V range, your signal will be extremely small within the resulting gain aperture to the point of being unusable. Similarly, if your voltage is going to span ±100V but your only range is ±50V, half of the signal will be clipped by the conditioner and will never be measured.

Aside from setting the input gain, perhaps the next most important function of a signal conditioner is to provide some manner of filtering. At the very least, a two or four-pole low-pass filter is often needed to suppress or reduce electrical noise, which can get into the signal from the testing environment.

One kind of filtering must be done in hardware, before the ADC process: anti-aliasing filtering. This is a special kind of filtering that prevents wrong readings that can happen when the sample rate is set too low compared to the frequency content of the signals being measured. Anti-aliasing filters (AAF) prevent wrong readings by automatically adjusting the front-end filter according to the selected sample rate. There are more details about AAF in the article called “What Is An A/D Converter?”

Virtually all other filtering can be done either in hardware or in software. For example, Dewesoft DAQ systems provide hardware filtering wherever it might be required by the application, for example, the high-pass hardware filters in their CHG (charge amplifier) and ACC (IEPE amp), which are useful for AC coupled accelerometer outputs prior to signal integration.

Other hardware filters are provided within Dewesoft DAQ hardware. But in addition, a powerful suite of software filters are provided for each channel. In fact, software filters can be applied non-destructively in Dewesoft DAQ systems, before or after recording (or both). This allows engineers to capture both the raw signal and one or more filtered copies of the signal, and compare them (as shown in the diagram above where a raw and filtered signal can be overlaid on the same graph).

Each signal conditioner must be perfectly adapted to the sensor with which it will be used. Sensors have vastly different requirements based on their operating principles, which the conditioner must be adapted to.

For example, a strain gage (aka strain gauge) signal conditioner must provide excitation voltage to the strain gage sensor. And since engineers use anywhere from one to four gages when making strain measurements, the conditioner needs to be adaptable to handle a quarter, half or full-bridge configuration.

Strain gages require perhaps the most complex setup in the world of signal conditioning, therefore the best conditioners provide a wide range of features including bridge completion, shunt cal, sense line hookup to suppress self-heating and sensor line resistance changes, and more.

Hard requirements such as isolation, sensor supply, input gain, and anti-aliasing must be done in hardware. Most filtering (except for anti-aliasing filtering) and linearization can be done in software.

If we look at voltage measurement, it would seem that this would be the easiest task because the signals already exist as a voltage. However, the voltage can span from very small potentials in the billionths of volts, up to tens of thousands of volts. It can also exist as an alternating current (AC) or direct current (DC).

Voltage potentials (electric potential) can exist far above the ground, or be centered around 0V. The challenges and therefore the processes are essentially the same as with any other physical phenomena that we want to measure. Small voltages must be amplified to a nominal digitizing level (typically ±5V). Galvanic isolation is often needed to prevent cross-talk and ground loops which can destroy the integrity of the measurement by introducing wrong values and offsets.

It is sometimes required to AC couple a voltage to remove the DC component or provide low or high-pass filtering in order to achieve certain measurement goals.

The SIRIUS LV DAQ module from Dewesoft is available with a variety of connector types to suit the application: BNC, safety banana jacks, DSUB9, and others upon request. For more information visit the SIRIUS tech specs page.

Large voltages must be stepped down to the nominal digitizing level. There are sensors for this, including potential transducers (PTs) which can divide the thousands of volts on an electrical transmission line down to a safe level. The output of a PT is then fed into the voltage signal conditioner, which further prepares it for digitizing.

Any signal conditioner used for high voltage measurement must be strongly isolated for the safety of the human operators of the equipment, and to avoid system damage or destruction.

It must be designed with the proper connectors. For temporary hook-up, safety/insulated banana jacks are common. For permanent hook-up, shielded screw terminals are common. Exposed contact connectors must be avoided.

A simple thermocouple sensor requires a high-quality signal conditioner in order to work. Although a T/C is passive, not requiring excitation or sensor supply, the tiny voltage potential that it generates at the connector side of the sensor must be isolated, amplified, and linearized. In addition, it needs a reference in order to provide an absolute temperature reading - otherwise, it can only produce a relative temperature reading, which is not very useful.

The amplification, isolation, and compensation aspects must be provided by the signal conditioner in hardware, while the linearization task can be done either in hardware or via software.

A tiny cold junction compensation (CJC) chip is provided here either inside the signal conditioner or within an annex box that connects to the conditioner. This CJC must be protected against ambient temperature swings caused by moving air or sunlight. They are typically installed within a special paste to keep their temperatures stable.

The science of making an accurate thermocouple signal conditioner cannot be overstated. Without serious attention to detail, accurate and linear thermocouple measurement cannot be made.

24-bit resolution is recommended with thermocouples. Why? A type K thermocouple sensor has a measuring range of -270° to +1260° C (-454° to 2300° F). That is a huge range.

Today, the mini blade thermocouple connector type has become the de facto standard, along with the color-coding that allows easy visual identification of the thermocouple type. Connecting a type K thermocouple into a signal conditioner that has been designed for Type S or T, for example, will result in wrong readings.

A “fixed type” thermocouple signal conditioner is one that has been made to be compatible with a specific thermocouple type, like Type J, K, or T, for example. Since Dewesoft offers high-performance universal signal conditioners for all of its DAQ systems, they have created DSI adapters for various sensors - including the most popular thermocouple types.

DSI-TH-x series adapters feature high accuracy cold junction reference measurement. 1 m thermocouple cable is included with a mini TC connector. Supported thermocouple types:

A good example of a universal type thermocouple signal conditioner is the KRYPTON isolated thermocouple modules from Dewesoft, available with 8 or 16 channels per module. These signal conditioners sample each channel at 100 S/s with a 24-bit resolution sigma-delta ADC per channel. Their input accuracy is typically ±0.02% of reading ±100 μV. They provide 1000V of isolation per channel, protecting the millivolt signals generated by thermocouples from interference.

Because the linearization can be performed very accurately and quickly by the included Dewesoft X data acquisition software, these modules are compatible with all major thermocouple types in use today: K, J, T, R, S, N, E, C, U, B.

White-color thermocouple connectors are used to indicate that the inputs are universal. The engineer simply selects the T/C TYPE that they are using on the channel setup screen within the Dewesoft X software, which then applies the correct linearization.

KRYPTON modules connect together via a single high-speed EtherCat interface, which carries power, data, and synchronization. They are made for harsh environments with high shock and vibration, water, dust, smoke, and from very low to high temperatures.

Although it also measures temperature, an RTD (resistance temperature detector) is a very different kind of temperature sensor compared with the thermocouple. The most important distinction is that RTDs are not passive sensors - they must be powered by the signal conditioner.

It supports both 3-wire and 4-wire RTD hookups. Note that 2-wire hook-ups are typically not recommended because the lead wire resistance gets added to the measurement resulting in artificially high-temperature readings, and there is no way to know exactly how much the measurement is wrong.

In a 3-wire hook-up, a third wire is used to detect the average lead wire resistance. The signal conditioner or accompanying software can then remove this offset in real-time, resulting in a much more accurate reading.

If we measure the resistance between R1 and R2 and subtract the resistance between R2 and R3, we will get the resistance of only the measuring end of the circuit at R(b). Of course, this assumes that the resistances are all the same. We can improve the accuracy even more by adding a fourth wire, as shown below:

You might notice that this hook-up is a full bridge. Lines 1 and 4 provide power to the circuit, and wires 2 and 3 are used to read back the lead wire resistance back to the RTD signal conditioner. In this way, we can completely offset variations in lead wire resistance.

So, if 4-wire hook-ups are always better than 3-wire, why do engineers sometimes opt for 3-wire? Usually, the answer lies in economics. If the RTDs are located a large distance from the measuring system, using three wires instead of four will save a lot of money in terms of cable cost and wiring cost. This can add up to a lot of time and money in large scale testing systems.

Accelerometer sensors that have a tiny amplifier built into them are also known as ICP® (a tradename of PCB Piezotronics) or more generically as IEPE, which stands for integrated electronics, piezo-electric. The output of these accelerometers is a relatively high-level voltage which can be sent back to the signal conditioner on good quality cable, at less expense than the cable required by charge type accelerometers.

But unlike charge type accelerometers that are passive and require no power, IEPE sensors need a voltage supply from the signal conditioner. This is normally presented in a form of a constant current of 4 to 20 mA and at a compliance voltage of 25 volts (typically).

Since IEPE accelerometers are made for measuring AC waveforms, this DC supply can be placed on the signal lines without creating any offset or measurement error.

Thus, the fundamental requirement of any IEPE signal conditioner is that it is able to provide this constant current power. The SIRIUS ACC provides a user-selectable constant current of 2, 4, 8, 12, 16 or 20mA at a 25 V compliance voltage.

Another useful feature, as provided on Dewesoft SIRIUS ACC modules, is a visual indicator that the sensor is connected and operating. SIRIUS DAQ modules do this by means of a green LED around the input connector bezel that lights up when the sensor is connected and working.

IEPE sensors nearly always employ a BNC connector, therefore it is important that the signal conditioner do the same. Referring to the picture above you can see the BNC input connectors on the SIRIUS ACC slice.

TEDS support is highly useful with IEPE sensors. TEDS (Transducer Electronic Data Sheet) is an IEEE 1451 standard based on storing information about the sensor inside the sensor itself, including its unit of measure, scaling factor, calibration information, and more.

The SIRIUS ACC signal conditioner can read this information when the sensor is connected, and automatically set up the sensor within the software. Dewesoft X software maintains a database of sensors that the user has connected, which can be managed by the user. TEDS is a huge time saver when many sensors must be connected in a short time, and also prevents set-up errors due to manual entry faults.

Input coupling is another important feature that the SIRIUS ACC conditioner provides. You can select from among DC (off), and two AC settings: 0.1 Hz and 1 Hz. Thus you can roll off low-frequency components close to the AC/DC threshold.

The frequency response of the signal conditioner. It does us no good to have a sensor that can measure up to 50 kHz when our signal conditioner cannot. So a bandwidth high enough to represent the top frequency signals of interest is clearly important.

SIRIUS ACC conditioners sample up to 200 kS/s/channel, providing an alias-free bandwidth of 70 kHz maximum. For higher speed applications, SIRIUS HS series signal conditioners provide sampling up to 1 MHz/s/ch using 16-bit SAR ADCs, with 100 kHz 5th order anti-aliasing filters.

One important aspect of measuring from virtually any sensor, but especially among dynamic ones like accelerometers is the dynamic range. This defines the maximum distance between the smallest and largest signals which can be measured. Each channel amplifier has two ADC"s that always measure the high and low gain of the input signal.

This results in the full possible measuring range of the sensor and prevents the signal from being clipped. With DualCoreADC® technology SIRIUS achieves more than 130 dB signal to noise ratio and more than 160 dB in dynamic range. See the video below.

24-bit ADCs provide an amazing resolution on the vertical axis. In addition, powerful anti-aliasing filtering on every channel adjusts to the selected sampling rate, preventing false signals caused by undersampling from destroying your measurements.

But the raw bit-count is just the beginning of the SIRIUS resolution story. For example, each input in a SIRIUS module literally has TWO 24-bit ADCs. One is set to a very high range, and one is set to a lower range.

The signal conditioner automatically uses the best amplitude signal from the dual-stream and creates a single stream of data with the best possible resolution. So to say that the SIRIUS has a 24-bit resolution is an understatement, since the result of this DualCoreADC innovation is amplitude axis resolution that is approximately 20 times better than systems with a single 24-bit ADC, with 20 times less noise.

Charge accelerometers require a signal conditioner that can read in their high impedance stream of charged ions (measured in pC, or pico coulombs), and convert them into a high-level voltage. They are based on the same piezoelectric principle as IEPE sensors (see above), but they have no built-in preamplifier. Therefore they do not require sensor power.

However, their high impedance output does not transmit as easily as the amplified output of IEPE sensors. Expensive low noise cables must be used and kept to as short a length as possible in order to prevent noise from influencing the signal. Still, charge accelerometers are still in use because they provide the highest possible temperature operating range, up to 538° C (1000° F), and the highest possible bandwidth. Specialty sensors are available with even greater operating temperature spans, low and high.

The SIRIUS CHG type signal conditioners are a great example of a versatile charge mode signal conditioner. In addition to handling charge sensors, it can also act as a low voltage conditioner and an IEPE signal conditioner.

There are three connectors commonly used by charge sensors: BNC, TNC, and 10-32. The SIRIUS CHG module is available with either BNC or TNC (essentially a threaded version of a BNC).

This is another important feature that the SIRIUS CHG conditioner provides. You can select from among 0.01 Hz, 0.03 Hz, 0.1 Hz, 0.5 Hz, 1 Hz, 10 Hz, or 100 Hz. Thus you can roll off low-frequency components close to the AC/DC threshold. This is important if you plan to integrate or double integrate the signal because noise and offset will be multiplied dramatically by this process.

The frequency response of the signal conditioner. It does us no good to have a sensor that can measure up to 50 kHz when our signal conditioner cannot. So a bandwidth high enough to represent the top frequency signals of interest is clearly important. SIRIUS CHG conditioners sample up to 200 kS/s/channel, providing an alias-free bandwidth in excess of 80 kHz at that top rate.

One important aspect of measuring from virtually any sensor, but especially among dynamic ones like accelerometers is the dynamic range. This defines the maximum distance between the smallest and largest signals which can be measured.

Each channel amplifier has two ADC"s that always measure the high and low gain of the input signal. This results in the full possible measuring range of the sensor and prevents the signal from being clipped. With DualCoreADC® technology SIRIUS achieves more than 130 dB signal to noise ratio and more than 160 dB in dynamic range.

24-bit ADCs provide an amazing resolution on the vertical axis. In addition, powerful anti-aliasing filtering on every channel adjusts to the selected sampling rate, preventing false signals caused by undersampling from destroying your measurements.

But the raw bit-count is just the beginning of the resolution story on SIRIUS DAQ systems. For example, each input in a SIRIUS module literally has TWO 24-bit ADCs: one is set to a very high range, and one is set to a lower range. The signal conditioner automatically uses the best amplitude signal from the dual-stream and creates a single stream of data with the best possible resolution.

So to say that the SIRIUS has a 24-bit resolution is an understatement, since the result of this DualCoreADC innovation is amplitude axis resolution that is approximately 20 times better than data acquisition systems with a single 24-bit ADC, with 20 times less noise.

Strain gage signal conditioners have perhaps the most complex job in the world of data acquisition. First, they must support multiple hook-up schemes, from the relatively simple full-bridge configuration to quarter and half-bridge configurations, and each with several wiring options. And when something other than a full bridge hook-up is selected, they are expected to also provide the resistors that are needed to complete the Wheatstone bridge circuit.

Of course, it must be possible to adjust the gain (aka sensitivity) of the signal conditioner. And to adjust how much voltage is sent to the strain gage sensor to power it (the excitation voltage). Filtering is almost always required with strain gauges, and this must be provided either in hardware or software, with selectable orders(filter strength).

That would seem like enough, but there are more requirements yet, including the ability to connect to one or more sense lines and use them to offset lead wire resistance changes caused by cable length and/or self-heating. Also, every strain gage has a Gage Factor - a number around 2, which must be entered and used by the system to convert the raw mV/V return from the sensor to a microstrain reading.

As a general statement, it should be an option for the engineer to choose to use the gage factor or not or to scale the return from the sensor in any way that they choose. For example, strain gage conditioners are also used for load cells, in which case we might want to see the reading in weight - kg or lbs. Every option should be provided to the engineer.

LVDT (linear variable differential transformer) transducers are used to measure linear displacement/position over relatively short distances. They consist of a tube that contains a rod. The base of the tube is mounted to a fixed position, and the end of the rod is affixed to something that moves.

As the rod is pulled out from the tube or slides back in, the sensor outputs a signal that represents the position of the rod from its starting point to its maximum deflection. The rod does not touch the inside of the tube, making it virtually frictionless, and the LVDT itself contains no electronics, making it popular in harsh environments.

An LVDT signal conditioner must provide the AC excitation that the transducer requires for operation. This AC drives the primary coil, which induces an output from each of the secondary windings, which are located toward either end of the tube. The signal conditioner must be able to take in and scale the differential output signal appropriately for display and measurement.

A good example is the SIRIUS STG with the DSI LVDT adapter from Dewesoft. Since the STG module has almost everything needed to perform as an ideal LVDT signal conditioner. All we add is a small adapter called the DSI-LVDT to the input connector of the STG module in order to complete the signal conditioner for use with LVDTs.

The DSI-LVDT has a TEDS chip inside it. When plugged into the SIRIUS-STG, the signal conditioner reads the information from the chip and automatically sets itself up as an LVDT signal conditioner. The engineer can further perform zero balancings and EU input and scaling if they want to. The DSI-LVDT generates the 4 to 10 kHz excitation that the sensor requires, and allows phase adjustment via a small potentiometer.

For large scale LVDT signal conditioning, the Dewesoft DS-16xLVDTr uses a unique ratiometric architecture to eliminate several of the disadvantages associated with traditional approaches to LVDT interfacing. The DS-16xLVDTr combines 16 channels of DSI-LVDT adapters in a 1U 19” rack-compatible housing.

The main advantage of the new design is the asynchronous excitation signal provided from an external function generator to a BNC front connector (IN connector). When using multiple DS-LVDTr devices the EXC signal can be daisy-chained from the BNC OUT connector to the BNC IN connector on the other device.

There are 16 DSUB-9M male connectors on the front panel for the connection to the Dewesoft data acquisition system. Each connector includes a trimmer for phase adjustment. On the rear panel are 16 DSUB-9F (female) connectors for the LVDT sensor connection. DS-16xLVDTr supports measurements with full-bridge and half-bridge LVDT sensor types.

A string pot or string potentiometer is a sensor that measures distance. It is configured as housing that contains a reel of rugged string that is spring-loaded so that it automatically winds back into the housing when the string is released.

The housing is mounted in a fixed position, while the end of the string is attached to something that will move, such as door, or a bracket or other object that will move back and forth with respect to where the housing is mounted. A good example is a movement between the “truck” of train wheels and the body of the train, which rides above it on a suspension system.

While a string pot is similar in operation to an LVDT, it is different in how it works. While an LVDT uses a differential AC potential to measure the position of a sliding rod, a string pot uses variable resistance to measure how much string has been deployed.

And from a mechanical point of view, the LVDT’s rod must move along a plane parallel with its tubular housing, while the string pot’s string is free to move in a wide arc from its point of emergence from the housing.

In order to condition a string pot’s output, we need a signal conditioner that can provide the excitation needed to invoke a resistance change from the sensor, and then read in the output. It is also necessary to be able to scale the reading into a useful unit of measurement, such as mm, cm, m, inches, feet, etc.

A good example is the SIRIUS STG module from Dewesoft. As a strain gage module, it is in the business already of providing excitation and reading in tiny voltage potentials. It can make resistance measurements in a basic half-bridge configuration. No additional adapter is needed in order to directly connect a string pot to the Dewesoft STG signal conditioner.

Digital inputs run the gamut from recording the simple on-off signals to handling a highly precise quadrature encoder, or gear tooth sensor that allows you to measure RPM, and other variants. They are referred to as digital because their signal is in the form of either high or low, unlike analog signals that have a waveform with many values between the highest and lowest ones which must be measured.

The simplest of digital inputs is the on/off type of signal that looks like a square wave if you look at it. These are sometimes referred to as discrete channels or event channels. Since they have only two states, they are often used to show the state of a door is open or closed, or a circuit being on or off, and a thousand other yes/no possibilities that we might need to measure.

Discrete inputs are normally output from a relay or transducer at TTL (transistor to transistor logic) levels, which are based on a 5V pull-up. In theory, the perfect TTL on/off signal would be 0V representing OFF (meaning a digital value of 0), and 5V representing ON (meaning the digital value of 1). However in practice, it is nearly impossible to achieve such precision, so the acceptable ranges have become 0 to 0.8V for OFF and 2V to 5V for ON.

These digital inputs are easily handled by Dewesoft’s SuperCounter® digital inputs, available on virtually every Dewesoft model DAQ system. These counter inputs have three lines (A, B, Z) which can handle encoders and RPM sensors - or you can use them as three separate discrete digital inputs (IN0, IN1, IN2). It is important to note that Dewesoft’s digital lines are sampled far above the sample rate selected by the user for their analog inputs, but are precisely aligned on the time axis with the analog inputs.

In addition, for large numbers of plain digital inputs, the Dewesoft IOLITE offers a 32 channel digital input module. This model 32xDI with easy screw terminal hookup and sensor power supply is ideal for high channel count data acquisition and control applications.

Dewesoft SuperCounter inputs can measure RPM and angle output values of rotating machines from a wide variety of RPM sensors, speed sensors, and encoders. Compared to standard counters, which only output integer numbers one sample later (e.g. 1, 1, 2, 2, 3, 4), SuperCounters can extract highly precise values like 1.37, 1.87, 2.37 between the analog samples, and fully synchronize them with the analog channels.

All of these can be connected to the Dewesoft SuperCounter and configured easily within the software. The outputs are perfectly synchronized with the analog data also being measured, allowing for advanced applications such as rotational and torsional vibration, combustion analysis, order tracking analysis, balancing, human body vibration, etc. to be performed.

Dewesoft X software has a built-in library of typical sensors, but it also has a flexible database that the engineer can use to create new sensors, name them, and call them up anytime in the future.

Texas’s power grid is unpleasantly surprising its users again. After last winter’s storm disabled parts of the grid for several days, causing potentially hundreds of deaths, a summer heat wave is once again threatening the grid. One potential solution Texas power companies have found is to turn up the temperature on some customers’ smart thermostats. Problem is, some of those customers weren’t aware that their power company could and would do such a thing — until their homes got uncomfortably warm.

One Houston family told a local news affiliate that their smart thermostat was turned up to 78 degrees with seemingly no notice other than a text sent after the fact. When they enrolled in a program called “Smart Savers Texas” — entering them in a sweepstakes to win up to $5,000 off their energy bills for the next year — these users didn’t realize that this also gave the power company permission to adjust their thermostat during high demand periods, like heat waves.

The idea of a power company turning up your thermostat like a stereotypical electricity-bill-conscious dad might seem dystopian, but it’s also fairly common. There are programs like Smart Savers Texas all over the country, from California to New England. The idea behind them is to decrease power consumption to alleviate stress on the electrical grid and avoid brownouts.

Since customers aren’t likely to volunteer to use less of the power they pay for when they need it most, these programs give them an incentive and the means to do so easily (by proxy). Some programs provide better incentives than others. When it launched in 2011, Philadelphia’s Smart A/C Saver program gave participants a $120 bill credit (apparently this was too generous, as it was reduced to $40 in subsequent years). But Smart Savers Texas only offers customers the chance to win free power for a year, and apparently it didn’t make its terms very clear.

But sometimes, the program’s terms were a little too good for customers. New York City’s Smart AC Program, which gave participants smart plugs and gift cards, ended in 2020 because, Con Edison said, it wasn’t cost-effective. Philadelphia’s PECO ended its similar program, with the $40 bill discount, last fall.

Power companies usually do these programs in partnerships with the tech companies that provide the devices. Smart Savers Texas is administered by a company called EnergyHub and is available through smart thermostats made by Alarm.com, Lux, Google’s Nest, Radio Thermostat, Sensi, Vivint, and ecobee.

Google’s Nest even has its own “Rush Hour Rewards” program available through participating power companies. The rewards vary. In one New York zip code, for instance, ConEd offers “up to” $85 if you enroll in the program, while National Grid is only giving out a $25 gift card. Some power companies also offer discounts on the smart thermostats themselves. And Google seems to hope there’s room to expand its Rush Hour Rewards beyond just temperature, too: Nest’s head of energy partnerships said in April that “in the future, your electric vehicle or even your whole home may be able to join in.”

These programs are currently opt in, unlike the aforementioned stereotypical electricity-bill-conscious dad. But if the Texas example is anything to go by, there are some people who didn’t realize what they were getting into. If you’re afraid you might be one of them and you don’t want to be, now would be a good time to check with your power company to make sure you aren’t, especially if you have a smart thermostat.

It’s also a good reminder to always check the fine print, especially if you’re being offered something for what appears to be nothing in return. There’s always a catch.

Millions turn to Vox to educate themselves, their family, and their friends about what’s happening in the world around them, and to learn about things that spark their curiosity. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all.

The main purposes of a Heating, Ventilation and Air-Conditioning (HVAC) system are to help maintain good indoor air quality (IAQ) through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools. The choice and design of the HVAC system can also affect many other high performance goals, including water consumption (water cooled air conditioning equipment) and acoustics.

The following actions detail how engineers can design a quality system that is cost-competitive with traditional ventilation designs, while successfully providing an appropriate quantity and quality of outdoor air, lower energy costs and easier maintenance.

The national consensus standard for outside air ventilation is ASHRAE Standard 62.1-2010, Ventilation for Acceptable Indoor Air Quality and its published Addenda. This standard is often incorporated into state and local building codes and specifies the amounts of outside air that must be provided by natural or mechanical ventilation systems to various areas of the school, including classrooms, gymnasiums, kitchens and other special use areas.

Many state codes also specify minimum energy efficiency requirements, ventilation controls, pipe and duct insulation and sealing and system sizing, among other factors. In addition, some states and localities have established ventilation and/or other IAQ related requirements that must also be followed.

Design in accordance with ASHRAE standards Design systems to provide outdoor air ventilation in accord with ASHRAE Standard 62.1-2007 and thermal comfort in accord with ASHRAE Standard 55–1992 (with 1995 Addenda) Thermal Environmental Conditions for Human Occupancy.

In some parts of the country, where temperature and humidity levels permit, natural ventilation through operable windows can be an effective and energy-efficient way to supplement HVAC systems to provide outside air ventilation, cooling and thermal comfort when conditions permit (e.g., temperature, humidity, outdoor air pollution levels, precipitation). Windows that open and close can enhance occupants" sense of well-being and feeling of control over their environment. They can also provide supplemental exhaust ventilation during renovation activities that may introduce pollutants into the space.

However, sealed buildings with appropriately designed and operated HVAC systems can often provide better IAQ than a building with operable windows. Uncontrolled ventilation with outdoor air can allow outdoor air contaminants to bypass filters, potentially disrupt the balance of the mechanical ventilation equipment and permit the introduction of excess moisture if access is not controlled.

Strategies using natural ventilation include wind driven cross-ventilation and stack ventilation that employs the difference in air densities to provide air movement across a space. Both types of natural ventilation require careful engineering to ensure convective flows. The proper sizing and placement of openings is critical and the flow of air from entry to exit must not be obstructed (e.g., by closed perimeter rooms).

Designers should consider the use of natural ventilation and operable windows to supplement mechanical ventilation.Consider outdoor sources of pollutants (including building exhausts and vehicle traffic) and noise when determining if and where to provide operable windows.

In most parts of the country, climatic conditions require that outdoor air must be heated and cooled to provide acceptable thermal comfort for building occupants, requiring the addition of HVAC systems. The selection of equipment for heating, cooling and ventilating the school building is a complex design decision that must balance a great many factors, including:

Where feasible, use central HVAC air handling units (AHUs) that serve multiple rooms in lieu of unit ventilators or individual heat pumps. Although there are many different types of air handling units, for general IAQ implications in schools, air handling units can be divided into two groups: unit ventilators and individual heat pump units that serve a single room without ducts; and central air handling units that serve several rooms via duct work.

Unit ventilators and heat pumps have the advantage of reduced floor space requirements and they do not recirculate air between rooms. However, it is more difficult to assure proper maintenance of multiple units over time and they present additional opportunities for moisture problems through the wall penetration and from drain pan and discharge problems. Central air handling units have a number of advantages as compared to unit ventilators and heat pumps serving individual rooms, including:

Easy access doors - All access doors are hinged and use quick release latches that do not require tools to open. Easy access to filters, drain pans and cooling coils is imperative.

Tightly sealed cabinet - Small yet continuous air leaks in and out of the AHU cabinet can affect IAQ and energy. The greatest pressure differentials driving leaks occur at the AHU.

Minimum 2 inch thick filter slots - For better protection of the indoor environment, as well as the equipment and ducts, the filters slots should be able to accommodate 2 in. or thicker filters.

Extended surface area filter bank - To reduce the frequency of filter maintenance and the cost of fan energy, the bank is designed to allow more filter area, such as the deep V approach or bags.

Air filter monitor - A differential pressure gauge to indicate the static pressure drop across the filter bank. This feature could easily be installed as an option in the field.

Corrosion resistant dampers and links - All moving parts such as pivot pins, damper actuators and linkages are able to withstand weather and moisture-induced corrosion for the full life of the system.

Indoor air can be two to five times more polluted than outdoor air; therefore, most HVAC system designers understand that increased amounts of outdoor air supply is generally better for IAQ. Yet there are concerns over the implications that this added amount of outdoor air supply has on the first cost and operating cost of the HVAC system, as well as moisture control for the school (too wet or too dry).

As a result, school designers often try to reduce the amount of outdoor air equal to — or even below — 15 cubic feet per minute (cfm) of outside air per person, the minimum for school classrooms, as established by the American Society of Heating, Refrigerating and Air -conditioning Engineers (ASHRAE) ASHRAE. In many parts of the country these concerns can easily be addressed by application of basic engineering principles and off-the-shelf HVAC equipment.

First cost, energy costs and moisture control do not have to be at odds with good IAQ. Energy recovery ventilation equipment can make the negative implications of 15 cfm per person of outdoor air behave like 5 cfm, while retaining the IAQ advantage of 15 cfm. This approach has been proven in many schools in various regions east of the Rockies, where advanced HVAC systems cost roughly the same as conventional systems, yet provide significant operating cost savings and IAQ advantages.

Proper location of outdoor air intakes can minimize the blockage of airflow and intake of contaminated air. The bottom of air intakes should be at least 8 inches above horizontal surfaces (generally the ground or the roof) to prevent blockage from leaves or snow. In northern locations, more separation may be needed due to greater snow depths or drifting snow.

Intakes should not be placed within 25 feet of any potential sources of air contaminants, including sewer vents, exhaust air from the school, loading docks, bus loading areas, garbage receptacles, boiler or generator exhausts and mist from cooling towers. If the source is large or contains strong contaminants, or if there is a dominant wind direction in the area, the minimum separation distance may need to be increased. Air admittance valves, an inexpensive and code-approved one-way air valve, can be added to sewer vents to eliminate the potential for release of gases into the surrounding air.

Grilles protecting air intakes should be bird- and rodent-proofed to prevent perching, roosting and nesting. Waste from birds and other pests (e.g., rats) can disrupt proper operation of the HVAC system, promote microbial growth and cause human disease. The use of outdoor air intake grilles with vertical louvers, as opposed to horizontal louvers, will reduce the potential for roosting.

Consider adding a section of sloped intake plenum that causes moisture to flow to the outside or to a drain if intake grilles are not designed to completely eliminate the intake of rain or snow.

In spaces where the number of occupants is highly variable such as gyms, auditoriums and multipurpose spaces, demand controlled ventilation (DCV) systems can be used to vary the quantity of outside air ventilation in these spaces in response to the number of occupants. One technique for doing this is to install carbon dioxide (CO2) sensors that measure concentrations and vary the volume of outside air accordingly.

If an auditorium fills up for school assembly, then CO2 concentrations will increase, a signal will be provided to the HVAC system and outside air volumes will be increased accordingly. When the spaces served by an air handler have highly variable occupancy, this type of control can both save energy and help control moisture (and mold) by reducing the quantity of humid outside air when it is not needed for ventilation. CO2 and other sensors must be periodically calibrated and maintained.

In addition to "atmospheric dust," airborne particulates can include pollen, mold (fungal) spores, animal dander, insect proteins, pesticides, lead and infectious bacteria and viruses. Designers can integrate features into the ventilation system that will provide benefits for the school occupants as well as the efficiency and longevity of the HVAC system. In addition, these features can reduce the need for expensive cleaning of the duct work and air handling units.

Air filters should have a dust-spot rating between 35% and 80% or a Minimum Efficiency Rating Value (MERV) of between 8 and 13. The higher the rating, the better the protection for the equipment and the occupants. It has been estimated that a 30% increase in static pressure across a coil results in a $200 per 10,000 cfm of air movement (at 7 cents per KWH). This does not include the added cost of cleaning dirty heating or cooling oils, drain pans, or air ducts. Designers should consider specifying a low efficiency (~10%) pre-filter upstream of the main filters. The pre-filters are generally easy and inexpensive to change and will capture a significant amount of the particulate mass in the air thereby extending the useful life of the more expensive main filters.

Design more filter surface area into ventilation systems. This has two advantages: the number of filter changes each year is reduced, thereby reducing the cost of labor to properly maintain the filters; and static pressure loss is lower, which saves money by reducing the amount of power needed to operate fans and blowers. Since different filter media are approximately proportional in their efficiency/pressure drop ratio, the most effective method for reducing pressure drop is to design more filter surface area into the filter system. This can be done by the specification of a filter with larger amounts of surface area, such as a pleated filter or bag filter. The next method is to increase the number and/or size of the filters in the airstream, for example, by mounting the filter slots in a "V" pattern, rather than a filter rack that is simply flat and perpendicular to the airstream.

Consider installing a simple pressure differential gauge across all filter banks. This will prevent school facilities personnel from having to guess whether the filter is ready for replacement. A gauge with a range of zero to 1.0 in. w.g. can save money and the environment by preventing premature disposal of filters that still have useful life and can prevent health and maintenance problems caused by overloaded filters that have blown out. The gauge should be easily visible from a standing position in an easily accessed location near the air handling unit.

The most effective means of reducing exposure of occupants to gases and VOCs is to manage and control potential pollution sources. Filters are available to remove gases and volatile organic contaminants from ventilation air; however, because of cost and maintenance requirements, these systems are not generally used in normal occupancy buildings or schools. In specially designed HVAC systems, permanganate oxidizers and activated charcoal may be used for gaseous removal filters.

Some manufacturers offer "partial bypass" carbon filters and carbon impregnated filters to reduce volatile organics in the ventilation air of office environments. Gaseous filters must be regularly maintained