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Model 202A-S is a low-cost 3 1/2 digit panel meter in a short 4.1 in (104 mm deep) 1/8 DIN case for applications that require bridge excitation and resolution down to 10 microvolts. Zero, span and bridge-balance adjustments are accessible behind the lens, so that the 202A-S can read out directly in engineering units for a wide range of bridge inputs or other low-level signals.
Applications
Model 202A-S is primarily intended as a digital indicator for pressure cells and metal-foil load cells. It can also be used as a low-level, high-impedance process meter with zero and span adjustments, or as a DC voltmeter with resolution down to 10 microvolts, required by 50 mV current shunts.
Resolution and Accuracy
Resolution is 1 part in ±1,999 counts, or 0.05% of full scale. Accuracy is 99.9%. A ratiometric reference input eliminates AC line and load regulation errors and reduces overall meter span tempco to 0.01% of reading/°C.
Bridge Excitation Supply
The built-in excitation supply of the 202A-S is transformer-isolated to 500 Vac from the rest of the meter. A multiturn potentiometer accessible behind the lens allows adjustment of the output voltage from 10 to 24 Vdc. Maximum output current is 30 mA.
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Mircovolt Preamplifier
The preamplifier of the 202A-S provides an input impedance in excess of 1 G to ensure that the signal source is not overloaded. Gains of 1, 10 and 100 are selectable by solder bridges and provide resolutions of 1000, 100, and 10 µV/count, respectively. Typical offset drift is only 0.3 µV/°C.
Options
Mechanical options are a PCB edge connector for handshake signals and a splash-proof lens cover which meets NEMA-4 requirements. Power options are isolated 9-32 Vdc and 26-56 Vdc.
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OMEGADYNE™ Load Cells
available from NEWPORT®
CLICK HERE FOR SELECTION GUIDE
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| SPECIFICATIONS
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Analog Input |
Most-Sensitive Scaling |
Least-Sensitive Scaling |
Range |
±19.99 mV |
2.5 V (limited by CMV) |
Resolution |
10 µV/count |
1 mV/count |
Preamplifier Gain |
100 |
1 |
Gain Attenuator |
1 |
0.001 |
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Configuration: Differential, ratiometric
Polarity: Bipolar
Input resistance: 1 G
Bias current: 1 nA typ, 5.5 nA max
Maximum voltage: 50 V
Coarse preamplifier gains: 1, 10, 100
Gain attenuator: Adjustable from 0.001 to 1
Bridge-balance range: ±50% of bridge span
Zero-adjustment range: -1,000 to +1,000 counts
Span-adjustment range: 0 to 2,000 counts
NOISE REJECTION
NMR, SIG HI to SIG LO: 70 dB, 50/60 Hz
CMR, SIG GND to SIG HI: 120 dB at gain 100, DC to 60 Hz
CMV, SIG GND to SIG HI or LO: +2.5 Vdc
CMR, SIG GND to PWR GND: 120 dB, DC to 60 Hz
CMV, SIG GND to PWR GND: 1500 Vp test, 354 Vp per IEC spacing
ACCURACY AT 25°C
Error, max: ±0.05% of reading ±1 count
Balance tempco: ±0.3 µV/°C typ, ±1.0 µV/°C max
Zero tempco: ±0.01% of zero/°C
Span tempco, ratiometric: ±0.03% of reading/°C
Span tempco, non-ratiometric: ±0.3 µV/°C
Full-scale step response: 1.0 s
Warmup to rated accuracy: 10 min
ANALOG-TO-DIGITAL CONVERSION
Technique: Dual-slope, average-value
Signal integration period: 100 ms
Read rate: 2.5/s
BRIDGE EXCITATION SUPPLY
Output voltage: Adjustable 10 to 24 Vdc
Output current: 30 mA at 10 Vdc decreasing to 12 mA at 24 Vdc
Line regulation: ±0.01%/V of AC power
Load regulation: ±0.5%
Ripple at 50/60 Hz: ±0.01%
Tempco: ±0.02%/°C
Reference signal: 1.0 V typ at 10 V output (Eliminates line and load regulation errors and reduces overall meter span tempco to ±0.01%/°C)
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DISPLAY
Display Type: 7-segment, red LED
Display Height: 0.56 in (14.2 mm)
Symbols: -1.8.8.8
Decimal points: Three positions, programmable by jumpers behind lens or at connector, 10 mA sink
Overrange indication: Three least-significant digits blanked
DIGITAL INPUTS
Level: TTL or 5 V CMOS compatible
POWER
AC voltages: 115 or 230 Vac ±15%
AC frequency: 49-440 Hz
DC voltages: 9-32 Vdc, isolated to 300 Vp; 26-56 Vdc, isolated to 300 Vp
Power consumption: 3.7 W max
Output Voltages: +4.7 Vdc and -4.7 Vdc ±5%, 10 mA max
ENVIRONMENTAL
Operating temperature: 0 to 60°C
Storage temperature: -40 to +85°C
Relative humidity: 95% at 40°C (non-condensing)
MECHANICAL
Dimensions: Newport DIN2A (1/8 DIN) case (see Mechanical section for drawings)
Weight: 15 oz (425 g)
Case material: 94V-0 UL-rated polycarbonate
Connector for signal and power: D4 screw-terminal barrier strip (standard)
Connector for control lines: D1 36-pin PCB edge connector (optional)
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† All dollar amounts on this site are shown in US currency.
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Part Number Builder |
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Option Descriptions
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(1)
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Model
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Select
202A for standard model
302 for model with INFINITY® Style Bezel and Adapter
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(2)
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Input Configurations
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Select
-S for Strain/Microvolt Meter with Excitation Output
-P for Process Receiver
-E for Process Receiver with Excitation Output
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(3)
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POWER
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Select
Nothing(leave field blank) for 115 Vac, 50/60 Hz
,C1 for 230 Vac, 50/60 Hz
,C3C for Isolated 9-32 Vdc
,C3E for Isolated 26-56 Vdc
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(4)
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ADD-ON OPTIONS
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Select
Nothing(leave field blank) for Red LED display
,G for Green LEDs for display
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(5)
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ADD-ON OPTIONS
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Select
Nothing(leave field blank) for No Options
,BL for Lens without Newport logo
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(6)
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ADD-ON OPTIONS
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Select
Nothing(leave field blank) for No Options
,FS for Custom calibration for models 202A-S / 302-S. Specify in millivolts for min/max input, and min/max display, and excitation of 10-24 Vdc. Specify decimal point position for display. $45
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| NOTE: All combinations may not be valid, check spec sheet for valid part numbers. |
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Keywords: Low-cost 3 1/2 Digit Strain / Microvoltmeter
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