Model 202A-O - 3 1/2 Digit Ohmmeter

3 1/2 DIGIT OHMMETER
MODEL 202A-O

1/8 DIN (2A) Case

Connections Diagram

QUANTA STANDARD FEATURES
1,999-count display span
19.99 ohm to 19.99 kohm ranges
2-, 3- or 4-wire connection
120 dB CMR, 70 dB NMR
1 mV/deg count output
Bright, 0.56 in (14.2 mm) LED display
Display hold and test
115/230 Vac power
EMI/RFI filter for AC power
Screw-terminal barrier strip
Short (4.1 in deep) 1/8 DIN case

OPTIONS

Isolated 9-32 Vdc or 26-56 Vdc power

NEMA-4 splash-proof lens cover

Model 202A-O is a low-cost 3 1/2 digit (1,999-count) resistance meter with readout directly in ohms. Four ranges are jumper-selectable: 19.99 ohms, 199.9 ohms, 1.999 kOhm, 19.99 kOhm. It is complete with low-level current excitation and open-resistance indication. The current source is tied to the reference of the A/D converter for true ratiometric operation and immunity to changes in line voltage.

STANDARD FEATURES
Electrical features include linearized analog output of 1 mV per count, which is ideal for driving a strip-chart recorder. Mechanical features include a bright 0.56 in (14.2 mm) LED display, a screw-terminal barrier strip for signal and power, and a compact 1/8 DIN case that requires a depth of less than 4.1 in (104 mm) behind the bezel.

OPTIONS
Options are isolated 9-32 Vdc or 26-56 Vdc power, a PCB edge connector for display control and output of +4.7 Vdc and 4.7 Vdc, and a splash-proof lens cover which meets NEMA-4 requirements.

SPECIFICATIONS

INPUT

Range	19.99 ohm	199.9 ohm	1.999 Kohm	19.99 Kohm
Resolution	10 mohm	100 mohm	1 ohm	10 ohm
Excitation Current	4mA	4mA	40 µA	40 µA
Zero Adjust	±2.5 ohm	±2.5 ohm	±250 ohm	±250s ohm

Connection: 2-, 3- or 4-wire
Excitation current: 4 mA or 40 µA
Resistance break indication: Meter displays overrange
Overvoltage protection: 25 Vp

NOISE REJECTION
NMR: 70 dB, 50/60 Hz
CMR, ANA GND TO PWR GND: 120 dB to 60Hz
CMV,ANA GND TO PWR GND: 1500 Vp per HV test, 354 Vp per IEC spacing

ACCURACY AT 25°C
Span tempco: ±0.01% of reading/°C
Zero tempco: ±1 m/°C (19.99 Kohm & 199.9 ohm ranges), ±0.1 ohm/°C (1.999 kohm & 19.99 kohm ranges)
Full-scale step response: 1 s
Warmup to rated accuracy: 10 min

ANALOG OUTPUT (Linearized)
Voltage: 1 mV/count
Calibration error: Same as given under accuracy
Current: 1 mA maximum
Source resistance: 68 ohm

ANALOG-TO-DIGITAL CONVERSION
Technique: Dual-slope, average value
Signal integration period: 100 ms
Read rate: 2.5/s

DISPLAY
Type: 7-segment, red LED
Height: 0.56 in (14.2 mm)
Symbols: 1.8.8.8
Decimal points: Three positions programmable by jumpers or at connector
Overrange or break indication: Three least-significant digits blank

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
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: 94 V-0 UL-rated polycarbonate