| Specifications | 1551A Ex | 1552A Ex |
| Measurement range | -50 °C to 160 °C (-58 °F to 320 °F) | -80 °C to 300 °C (-112 °F to 572 °F) |
| Accuracy (1 year) | ±0.05 °C [± 0.09 °F] |
| Resolution | Selectable: 0.1, 0.01, 0.001 (default 0.01) |
| Sample rate | User selectable 0.5/sec, 1/sec or 2/sec. Factory default is 1/sec. |
| Probe hysteresis | ±0.01 °C |
| Response time | Approximately 20 seconds |
| Operating temperature range of readout | -10 °C to 50 °C (14 °F to 122 °F) |
| Humidity range | 0 to 95 % RH non-condensing |
| Storage temperature range | -20 °C to 60 °C (-4 °F to 140 °F) |
| Display units | °C, °F |
| Sensor type | 100 ? thin-film RTD | 100 ? wire-wound PRT |
| Sensor length | ? 10 mm | ? 30 mm |
| Sensor position (from sheath tip) | 3 mm (0.1 in) |
| Minimum immersion depth | Wet medium (liquid bath, thermowell with thermal compound) 70 mm (2.8 in) Dry medium (dry-well, thermowell without thermal compound) 120 mm (4.8 in) |
| Maximum immersion depth | 50 mm (2 in) less than the total length. Make sure the last 50 mm of probe, nearest to the internal electronics of the device, are not put into the heat source. | 75 mm (3 in) less than the total length. Make sure the last 75 mm of probe, nearest to the internal electronics of the device, are not put into the heat source. |
| Probe sheath material | Stainless steel |
| Optional data logging* | Up to 10,000 time-stamped readings stored to internal memory |
| Logging intervals* | 2 seconds, 5 seconds, 10 seconds, 30 seconds, or 60 seconds |
| Damping | Moving average of the most recent 2 to 10 readings (ON/OFF, 2, 5, 10) |
| Communications | RS-232 stereo jack (access calibration parameters only) |
| AC power | none |
| DC power | 3-AAA alkaline batteries. See Users Manual for approved batteries. |
| Battery life | Approximately 300 hours (12.5 days) of continuous operation with the backlight off |
| Safety | IEC 60079-0, IEC 60079-11: Ex ib IIB T4 Gb; IEC 61010-1: Pollution Degree 2 |
| Readout size (H x W x D) | 125 mm x 62 mm x 35 mm (5 in x 2.5 in x 1.4 in) |
| Weight | 200 g (6.9 oz) |
| Calibration (included) | NVLAP-accredited, NIST-traceable |
| Characterization | CVD | ITS-90 |
