3 1/2 Digit (Pt100) RTD Meters

3 1/2 DIGIT (Pt 100) RTD METERS
MODEL 202A-M, -R

1/8 DIN (2A) Case

Connections Diagram

STANDARD FEATURES
Platinum 100 ohm RTD input
1 mA excitation current
2-, 3- or 4-wire connection
200 to +820°C in 1°C steps (-M)
199.9 to +199.9°C in 0.1°C steps (-R)
°C or °F, jumper-selectable
Platinum curve linearization
120 dB CMR, 70 dB NMR
1 or 10 mV/deg linearized recorder output
Bright, 0.56 in (14.2 mm) LED
Display hold and test
115/230 Vac power
EMI/RFI filter for AC power
Screw-terminal barrier strip
Short 4.1 in (4.1 in deep) 1/8 DIN case

OPTIONS
Isolated 9-32 Vdc or 26-56 V power
NEMA-4 splash-proof lens cover

Models 202A-M and -R are low-cost 3 1/2 digit (±1,999 count) temperature indicators for use with platinum 100 ohm RTD's with alpha of 0.00385. They are complete with 1 mA sensor excitation, sensor-break detection, and platinum curve linearization. Resolution is 1° (-M) or 0.1° (-R). Readout can be in °C or °F, as selected by push-on jumpers. The electrical connection can be by 2, 3 or 4 wires. High accuracy is provided by positive current feedback and matched, graded components.

STANDARD FEATURES
Mechanical features include a bright 0.56 in (14.2 mm) display, a screw-terminal barrier strip for signal and power, and a compact 1/8 DIN case that requires less than 4.1 in (104 mm) behind the panel. Electrical features include jumper selection of °C or °F, a linearized recorder output of 1 or 10 mV per degree, and 1 mA current excitation. The current source is tied to the reference of the A/D converter for true ratiometric operation and immunity to changes in line voltage.

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 power, and a splash-proof lens cover which meets NEMA-4 requirements.

SPECIFICATIONS

INPUT
RTD type: 100- platinum with alpha of 0.00385
Calibration: IEC 751 (IPTS-68)
Configuration: 2-, 3- or 4- wire connection
Polarity: Bipolar
Zero: Adjustable ± 20°C (±36°F)
Zero tempco: ±0.05 degree/degree (-M) ,±0.01 degree/degree (-R)

Sensor-wire resistance tempco effect per conductor:
2-wire: 20 mdeg/ ohm /deg, up to 3.8 ohm
3-wire: 50 µdeg/ ohm /deg, up to 100 ohm
4-wire: 5.0 µdeg/ ohm /deg, up to 100 ohm
Sensor-excitation current: 1 mA
Sensor-break indication: Meter displays overrange
Overvoltage protection: 25 Vp

NOISE REJECTION
NMR, SIG HI to SIG LO: 70 dB, 50/60 Hz
CMR, ANA GND to POWER GND: 120 dB DC to 60 Hz
CMV, ANA GND to ANA GND: 1500 Vp per HV test, 354 Vp per IEC spacing

ACCURACY AT 25°C
Span tempco: ±0.005% R/°C on all models plus ±0.05°C/°C for -RC from 200 to 130°C
Celsius/Fahrenheit: Jumper-selectable
Full-scale step response: 1 s
Warmup to rated accuracy: 10 min

ANALOG OUTPUT (Linearized)
Voltage: 1 mV/deg (-M); 10 mV/deg (-R)
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: XXXX (-M); XXX.X (-R)
Overrange 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 to 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 (short 1/8 DIN) case (see Mechanical section for drawings)
Weight: 15 oz (425 g)
Case material: 94V-0 UL-rated polycarbonate