4-1 2 digit lcd panel meter factory

A man with one voltmeter knows his voltages. Perfectly. When, due to the pressures of circumstances, he acquires one more, he doesn"t, any longer. Each meter will have its own interpretation of the voltage presented to it, and this can cause confusion when relying upon them to perform critical tasks such as charging Li-Po batteries.

This instructable describes a Four-and-a-half digit voltmeter based on the MAX1498 ic from Maxim. It comes calibrated from the factory and all you need to do is to add the components to supply power to it, and to display the output from it.

With four and a half digits, this meter can display counts upto 19999, plus or minus. The "and half" part of the designation comes from the fact that the first display, used to indicate the sign (+ or -) can, without much effort, be used to display a "1" as well.

Since most multimeters used for servicing are of the three and a half digit variety this little circuit can be used to keep a bunch of them agreeing with each other.

The figure shows the pinout of the ic. Eight outputs for the seven segments and decimal point. Five outputs for the display cathodes. Five supply connections. Two inputs. A few digital inputs to control the behaviour of the chip. The data sheet will have the full details if you wish to probe further.

I printed out the pin diagram and drew the external connections in. Peak and hold inputs were held inactive. The internal reference was used. The decimal points were set to be displayed, and the 2V/ 200mV selection would be by an external switch.

The two analogue input pins are not soldered to the board. Two wires connect this to a separate piece of glass epoxy board which carries two 330 ohm resistors and 100n capacitors to ground. In addition, the neg input has been given a "static leak" via a 1Meg resistor. The chip will work from 2.7 V to 5.5V, so I intend to power it from three or four AA cells.

Finally, it works. In the pictures, it is displaying the voltage of a single dry cell and the display holds steady. As you can see, there is a change of just one count in that last digit.

I might be wrong, but I cannot find any reference to the 1498 being calibrated at the factory. You are using the internal voltage reference which can vary anywhere between 2.007V and 2.089 with 2.048 being the nominal voltage. I see that it has offset calibration but that can"t be confused as span calibration. If your reference voltage can vary +-2% then your measurements can off be 2%. This only gives you about 3 digits of accuracy

Applications The digital panel meters RISH DPM have been designed for industrial applications, which frequently require precise and on-site adjustment of the display range. It can be used in industrial automation and for laboratory uses. Features

Distributor of digital panel meters for pharmaceutical, petroleum, agricultural, government, food and beverage industries. Types include large display process, temperature, high voltage DC, serial input, strain gage, 3 1/2, 4 1/2 and 5 digit loop powered panel meters. Available in 4 to 20 mA input current, various input voltages, power supplies, operating temperatures, LED or LCD display heights and voltage drops. Suitable for water, wastewater, natural gas, power generation, metal milling, transportation, plastic forming, packaging, compressor, pump, OEM, research and development applications. Some panel meters are CE certified, CSA approved and UL listed.

A digital indicator, sometimes also referred to as a panel meter, is an instrument that acts as the display unit for process application equipment. Digital indicators accept input

from a wide range of probes, transducers, thermocouples, strain gauges, potentiometers, and other sources and convert their electrical signals into the proper engineering units to provide

Generally speaking, digital indicators can be configured to accept input from nearly any type of equipment though some models are designed for use in specific applications such as flow

meters. Some indicator models boast of universal input capable of accepting linear input, such as voltage or current, as well as input for all thermocouples and RTDs. Depending upon the

indicator, input type can be either programmed into the meter or needs to be selected at the time of ordering the meter. Other indicators are capable of reading other inputs such as pulse / frequency

Digital indicators are an easy way to provide remote readout of measured values for permanently installed equipment. Indicators are most commonly installed inside an instrument panel

(hence the name “panel meters”), offering a centralized location away from noise and hazards from which to monitor one or more processes. Some models are available with NEMA rated enclosures

Many digital indicators also offer a range of communications and advanced features to increase the versatility of the meter. For applications in which the user wants to store data for later

recall or from which to create charts or reports, RS-482, RS-485, MODBUS, Ethernet, DeviceNet, and other communications options are available. If more than simply displaying measured values

is desire, many models offer alarms, set points, counters, scaling, and advanced math functions. Many digital panel meters can accept multiple inputs and have adjustable or bar graph displays

that allow users to easily switch between these inputs. It’s pretty easy finding a digital indicator that can be easily tailored to suit your exact process monitoring needs.

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The Simpson Mini-Max digital panel meters provide high quality accuracy and reliability in a compact, 60 mm deep case. The Mini-Max series is available with a LCD or LED display. The LCD units offer a 3-1/2 digit, 0.5″ (12.7 mm) display with an optional bright red, negative image backlight. The LED units offer a 3 1/2 digit, 0.56″ (14.2 mm) display. All units feature user-selectable decimal point, auto zero and limited scaling capabilities.

A unique mounting bracket is provided to allow for vertical or horizontal stacking of multiple indicators. All Mini-Max units feature a 3/64-DIN, high-impact plastic case. The LCD units have a clear viewing window, and the LED units have a red window.

Exceptional accuracy and high read rate with five digital voltmeter ranges from 200.00 mV to ±300.0 V and four digital ammeter ranges from ±2.0000 mA to ±5.000 A, all factory pre-calibrated. Shipped ready to run.

User-scalable for display to ±99,999 for process signals requiring zero and span adjustment, such as 0-1 mA, 4-20 mA, or 0-10 V. Ideal for use as a readout for pressure transducers (manometer applications) and flow meters. Includes 5, 10, 24V transducer excitation output (user-selectable).

Five AC RMS voltmeter ranges to 200.00 mV to 600.0 V and four AC RMS ammeter ranges from 2.0000 mA to 5.000 A, all factory pre-calibrated. 0.1% accuracy. Takes 5-digit readings in one AC line cycle. Shipped ready to run.

Exceptional accuracy RTD temperature meter for Pt100 100-ohm platinum RTDs (DIN or ANSI alpha), Ni120 nickel and Cu10 copper. User selectable RTD type, unit of measure (°F or °C) resolution (1° , 0.1° or 0.01°), and 2, 3 or 4-wire hookup to eliminate lead resistance effects. Pre-calibrated for all RTD types. Wide range of options for communication and temperature control. Shipped ready to run.

A high-sensitivity 5-digit meter for use with load cells, strain gauges and microvolt input signals where high accuracy and stability are required. Most sensitive full-scale range of ±20 mV. Load cell operation allows 4- or 6-wire hookup and display in engineering units, such as lbs, kg or psi. Built-in excitation for up to four 350-ohm load cells in parallel.

Factory calibrated for five jumper selectable resistance ranges from 20Ω to 200 kΩ. Exceptional accuracy of ±0.01% of full scale. In the 20-ohm range, resolution is 1 milliohm, making the meter suitable for contact resistance measurements. Custom curve linearization allows use with transducers whose output is a changine resistance. 3 or 4 wire connection eliminates lead resistance effects.

Equipped with a DC or load cell signal conditioner, this Laureate offers special firmware for scale / weighing applications: two tare functions; count by 1, 2, 5, 10, 20, 50 or 100; auto-zero function; setpoint offset, and dummy right-hand zero for display to 999,990. Built-in excitation for up to four 350-ohm load cells in parallel.

All capabilities of the Laureate process meter, plus custom curve linearization. Setup is easy using an external PC and linearizing software furnished by Laurel. For example, display liquid volume in irregularly shaped tanks, use with non-linear transducers, or extend the working range of nominally linear transducers.

Universal meter for 65 user-selectable analog input signal types and ranges: DC voltage and current, AC RMS voltage and current, process signals (4-20 mA, 0-10V), thermocouple (10 types, °C or °F), RTD (6 types, °C or °F), thermistors (NTC or PTC), resistance (0-10k or 0-100k ohms), and potentiometer inputs. Universal 18-265 Vac/dc power. 1/8 DIN case.

Available with four or six 57 mm (2.2"), 102 mm (4"), 150 mm (6"), or 200 mm (8") high digits for process signal, strain gauge, load cell, temperature, and pulse inputs. Optional dual 5A relays, analog output, and serial output. Choice of display brightness and cases for indoor or outdoor mounting.

Two independent scalable pulse-input channels from 0 Hz to 1 MHz. Channels may be combined arithmetically. One channel can display total while other displays rate. High read rate for control applications. Ideal for use as a tachometer or readout of a turbine flow meter.

Two independent scalable pulse-input channels. Count up or down to a preset at rates up to 1 MHz. Scaled rate and total from the same electronic counter. Scaling for direct readout in engineering units, such as gallons or cubic feet based on counts from a turbine flow meter. One channel can display total while the other displays rate.

Displays and totalizes 0-1 mA, 4-20 mA, or 0-10 V process signals. Square root extraction is standard for flow applications, allowing display of volume from the 4-20 mA signal of a flow transducer with a linear or squared output.

Arithmetic functions (+, -, /, x) on dual channels A and B open a world of possibilities. For example, add or subtract rates from two flow meters for combined scaled flow or volume. Display the ratio of flow rates, RPM of rollers, or speed of moving belts. Draw, which is obtained by subtracting 1 from ratio, can be used to indicate elongation or shrinkage of material as it passes between rollers.

A low-cost controller for repetitive fill operations. Provides a flow meter input and two built-in relays: a Prewarn relay to slow to down the pump near a preset to avoid overshoot, and a Batch relay to stop the pump at the preset. Fill cycles repeat after a programmed time interval or based on an external input.

Same capabilities as the Laureate pulse-input batch controller, but for 0-1 mA, 4-20 mA, or 0-10 V process signals, as made possible by a voltage-to-frequency (V-to-F) converter. Square root extraction is standard for use with flow meters.

Times events which produce start and stop pulses. Displays time in HH.MM.SS clock format with 1 sec resolution or in H, M or S format with six-digit resolution. Single-event times may range from 1 µs to 99 hours with a timing resolution to 0.2 µs. Multiple events can also be accumulated to 999,999 hours.

Exceptionally fast response (20 updates per second) for low frequencies, such as AC line frequency. Phase angle resolution of 1°, 0.1°% or 0.01°% is user-selectable. Phase angle accuracy is 0.01% up to 100 Hz, 0.1% at 1 kHz, and 1% at 10 kHz. Also power factor measurement from 1.000 to 0.000 with sinusoidal signals.

Available for all the same signals types as Laureate digital panel meters, counters and timers. Exceptional accuracy at high update rates. Standard features include an isolated 4-20 mA or 0-10V analog output, and isolated RS232 or RS485 serial output, and two AC/DC solid state relays for alarm or control. Easily set up via a PC using Instrument Setup Software.

Available for all the same signals types as Laureate digital panel meters, counters and timers. Exceptional accuracy at high update rates. Standard features includ and isolated 4-20 mA or 0-10V analog output, and isolated RS232 or RS485 serial output, and two AC/DC solit state relays for alarm or control. Serial interface standard. Easily set up via a PC using Instrument Setup Software.

Accepts RS232 or RS485 serial data with Modbus or Custom ASCII Protocol, and converts it to an isolated, scalable 4-20 mA or 0-10V analog output signal.

These accept RS232 or RS485 serial data from computers, programmable controllers, and Laureate meters or counters to provide a visual display from -999,999 to +999,999. They can also be configured to provide alarms and analog outputs based on the serial data. Available with a red or green display

Available with four or six 57 mm (2.2"), 102 mm (4"), 150 mm (6"), or 200 mm (8") high digits for process signal, strain gauge, load cell, temperature, and pulse inputs. Optional dual 5A relays, analog output, and serial output. Choice of display brightness and cases for indoor or outdoor mounting.

Turns a PC connected to any mix of Laureate digital panel meters, counters, timers and transmitters into a powerful datalogging system. The Laureates can be connected to the PC in addressable multidrop fashion from a single RS485 line using either the Modbus protocol or the simpler Custom ASCII Protocol. The Laureates can also have an Ethernet interface and be connected into the same LAN as the host PC.