Electro-Numerics, Inc.
42213 Sarah Way, Temecula, CA 92590, USA

Tel: 800-854-8530 (USA)
Tel: 951-699-2437 
Fax: 951-695-7246

sales@electronumerics.com

    Micro Series Process, Strain Gauge
& Potentiometer Follower Meters

Panel Meters and large-digit displays with
scalable readout & control outputs

 

  
Features

  • Available in three digit heights: 0.56" for panel mounting, 1.0" (Mighty-1) or 5.0" (Mighty-5) for long-distance viewing.
  • 0.2, 2, 20, 200 and 660 V ranges.
  • 2, 20, 200 mA and 5 A ranges.
  • All ranges factory calibrated.
  • 4 1/2 to 5 digit resolution.
  • Scalable via front panel pushbuttons or computer for display in engineering units.
  • Span adjust from 0 to 99,999
  • Zero adjust from -99,999 to +99,999
  • Peak value display and auto-tare.
  • Up to 60 conversions per second.
  • Selectable fixed right-hand zero with rounding.
  • 5, 10 or 24 Vdc transducer excitation supply.
  • Ratiometric compensation for variations in excitation voltage.
  • External controls for reset, meter hold, decimal points, and tare.
  • Choice of isolated plug-in options for control and computer interface:
    dual relays, 4-20 mA & 0-10 V analog output, RS232/485 serial I/O, low voltage AC & DC power.
  • 1/8 DIN version environmentally sealed to NEMA-4X from front panel.
  • 1/8 DIN version certified to UL 3101-1, CAN/CSA-C22.2, EN 61010-1 (CE Mark).

Description

Signal conditioner for Laureate digital panel meter for process, strain, and potentiometer follower applicationsMicro Series digital process and strain panel meters are a cost-effective solution to a wide variety of monitoring and control applications which require a scalable readout from strain gauges or from process signals such as 4-20 mA, 0-5 V or 0-10 V. They are also ideal for use in potentiometer follower applications, where the transducer output is a changing resistance.

Scalable to Five Full Digits

The display may be scaled to five full digits from -99,999 to +99,999 from the front panel to read directly in engineering units, such as PSI. Three scaling methods are selectable: scale and offset, two-point method, and system-level calibration using actual transducer signals. All ranges are precalibrated at the factory, so that recalibration is not needed when changing ranges or signal conditioners.

With the Micro process meter, strain gauges with a 20 mV output can be scaled to display up to 10,000 counts, while outputs of 200 mV can be scaled to 99,999 counts. With the Micro load cell meter, strain gauges with a 20 mV output can be scaled to the full 99,999 counts.

Isolated Excitation Supply

5, 10, and 24 Vdc isolated excitation outputs are standard to power strain gauge bridges and 4-20 mA transmitters, eliminating the need for an external supply. When powering strain gauges or potentiometers, the 5 or 10 Vdc excitation is monitored by the meter to eliminate errors caused by excitation voltage variations.

Fast Read Rate and Signal Filtering

The displayed readings and the data outputs can be separately selected to be either unfiltered or filtered.

  • An unfiltered selection updates after each conversion for fastest response, up to 60/sec, while integrating the input signal over a full power cycle. Fast read rate provides true peak readings and aids in control applications.

  • A batch-average filter selection averages each 16 conversions for an update every 1/4 sec.

  • An adaptive moving average filter selection provides a choice of 8 time constants from 80 ms to 9.6 s. When a significant change in signal level occurs, the filter adapts by briefly switching to the shortest time to follow the change, then reverts back to its selected time constant. Another choice is Auto, which provides an automatic time constant selection based on the signal noise characteristics.

Advanced Meter Features

  • Auto-tare allows the display to be zeroed for any input signal. This is normally achieved by applying a switch closure or logic signal at the rear connector. The tare value is stored in non-volatile memory and is retained when power is removed.

  • Peak value of the input signal is automatically captured and may be displayed via a front panel pushbutton command or control signal at the rear connector. Other controls via the rear connector include meter hold, meter reset, peak reset, and decimal point selection.

Rate & Custom Curve Fit Options

An Extended Micro computer board can display rate based on successive readings. It also allows exceptionally accurate custom curve linearization, for example to read out liquid volume or rate of flow in a horizontal cylindrical tank based on level reported by a 4-20 mA transmitter. For setup, up to 240 data points can be input into a computer spreadsheet or text file by the user. The computer then calculates spline-fit segments, which are downloaded into the meter via RS232.

Built-in Flexibility

Plug-in isolated analog output, dual setpoint controller, and RS232/485 serial communications boards can upgrade the Micro and Mighty Series process meters from a stand-alone monitor to system interface and control.

Micro Series meters can be powered from 95-240 Vac 10% and 95-370 Vdc, or optionally from 12-34 Vac and 10-48 Vdc. Any setup functions and front panel keys may be locked out for simplified usage and security. The popular 1/8 DIN version with 0.56" high digits is environmentally sealed to NEMA-4X (IP65) from the front when panel mounted, and is available with red or green LEDs.

Specifications

DC Voltage
  
DC Voltage Range Resolution Input
Ohms
Error at 25C
1 count
200.00 mV
2.000 V
20.000 V
200.00 V
660.0 V
10 V
100 V
1 mV
10 mV
100 mV
1 G
1 G
1 M
1 M
1 M
0.01% FS
0.01% FS
0.01% FS
0.01% FS
0.03% FS

DC Current

DC Current Range Resolution Input
Ohms
Error at 25C
1 count
2.0000 mA
20.000 mA
200.00 mA
5.000 A
0.1 A
1.0 A
10 A
1.0 mA
100
10
1
0.01
0.01% FS
0.01% FS
0.01% FS
0.04% FS

DC Voltage & Current

Display
Readout
Digit Height
Color
Range
  
Indicators
5 digits, 7-segment
Available with 0.56", 1.0", 4.0" or 5.0" digits.
High brightness red. Green available with 0.56" digits.
-99999 to +99999
-99990 to +99990 (selectable count by 10 with rounding)
Minus sign, 2 red LED lamps
Readout
Color
Range
  
Indicators
5 digits, 7-segment, 14.2 mm (.56")
Red or green LED
-99999 to +99999 or -99990 to +99990 
(count by 10 with rounding)
Minus sign, 2 red LED lamps
A-to-D Conversion
Technique
A-to-D Rate
Output Update
Display Update
Concurrent Slope(Pat 5,262,780)
60/s at 60 Hz, 50/s at 50 Hz
56/s at 60 Hz, 47/s at 50 Hz
3.5/s at 60 Hz, 3/s at 50 Hz
Accuracy
Span Tempco
Zero Tempco
0.003% of reading/C
0.1 counts/C
Noise Rejection
CMR, DC to 60 Hz
NMR at 50/60 Hz
130 dB
90 dB with min filtering
Maximum Signal
Max applied voltage
Overcurrent protection
660 Vac for 20, 200 & 600 V ranges, 125 Vac other ranges.
25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5 A.
Power
Voltage, std.
Voltage, opt.
Frequency
Power isolation
95-240 Vac 10% and 95-370 Vdc
12-34 Vac and 10-48 Vdc
DC or 49-440 Hz
Safety-rated to 250 Vac, meter ground to earth ground,
DC to 60 Hz, 4.2 kVp per High Voltage Test
Excitation Output
5 Vdc
10 Vdc
24 Vdc
Output isolation
5 Vdc 5%, 100 mA max
10 Vdc 5%, 120 mA max
24 Vdc 5%, 50 mA max
50 Vdc to meter ground
Connector Pin Assignments
conrmsnobox.gif (904 bytes)
Environmental
Operating Temperature
Storage Temp.
Relative Humidity
Protection
0C to 60C
-40C to 85C
95% at 40C, non-condensing
NEMA-4X (IP-65) when panel mounted

Application Examples

Wiring a Laureate digital panel meter for a potentiometric pot follower application
Potentiometer Application

In potentiometric (or pot follower) applications, the signal from a sliding contact voltage divider can be converted to engineering units such as position, level or percentage. By operating in a ratiometric mode, the meter will remove any effects caused by variations in the excitation supply output.

For use with a 1 kohm potentiometer, the recommended applied excitation voltage is 10 V, and a 2 kohm resistor should be placed in series with the excitation output and excitation return leads. This will allow the meter's 2.0000 V scale with a high input impedance of 1 Gohm to be used.

dcdraw4.gif (1014 bytes)

Using a digital panel meter to power a two-wire transmitter

Using a digital panel meter with peak detection for destructive testing
Powering two-wire transmitters
 
The isolated 24 Vdc, 50 mA excitation output, which is standard with all Micro meters, is ideal for powering two-wire, 4-20 mA transmitters. The same two wires are used to apply voltage and carry the output current. Inside the meter, the 4-20 mA current is dropped across a 10
ohm resistor and sets up a 40-200 mV voltage, which is then sensed by the meter and scaled to engineering units.
Testing with peak detection
 
Destructive testing is an ideal application for the Micro strain meter. Peak readings are automatically captured at rates up to 60 per second, while the display updates at a legible 3.5 readings per second. The peak reading can be recalled at the push of a button or be transmitted via RS232 or RS485.
The meter provides isolated 10 Vdc power for up to four (4) the strain gauges and can be scaled to read out directly in engineering units from -99,999 to +99,999.
Using a linearizing digital panel meter Using digital panel meter to obtain rate from successive readings
Custom curve linearization

The Micro DC meter with the Extended main board option allows exceptionally accurate custom curve linearization. For setup, up to 240 data points can be entered into a spreadsheet. The system then creates multiple non-linear spline-fit segments, which provide much better accuracy than linear segments.

One application, as illustrated, is the readout of volume of irregularly shaped tanks based on measured liquid level or pressure. Altimeters and thermistors are further applications.

Rate from successive readings

The Extended computer board allows the display of rate based on successive readings, for instance flow rate based on changes in liquid level or static pressure in a tank.

In the above illustration, the meter displays the rate in gallons at which a horizontal tank is being emptied. The input to the meter can be nonlinear, since only the linearized readings are compared for the determination of rate.

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Electro-Numerics, Inc., 42213 Sarah Way, Temecula, CA 92590
Tel: 800-854-8530 (USA), 951-699-2437;  Fax: 951-695-7246;  sales@electronumerics.com