Installation notes
- This Intrinsically Safe CHARM requires the I.S. CHARM Thermocouple / mV Terminal Block.
- Cold Junction Compensation for the CHARM is built into the terminal block.
- Color coding for thermocouple wires varies from country to country. Refer to your local standards for the appropriate color code.
- At rates of temperature change greater than 126 °C/s, the CHARM may temporarily indicate an open loop.
Specifications
| Item | Specification |
|---|---|
| Channel type | I.S. Thermocouple input |
| Sensor types |
Thermocouple: B, E, J, K, N, R, S, T, uncharacterized
mV: Low level voltage source (±20 mV, ±50 mV, and ±100 mV). |
| Full scale signal range | Depends upon Thermocouple sensor type. Refer to Table: I.S.Thermocouple sensor type specifications |
| Accuracy over full scale temperature range | Depends upon Thermocouple sensor type. Refer to Table: I.S.Thermocouple sensor type specifications |
| Repeatability | 0.05% of span |
| Resolution | Depends upon Thermocouple sensor type. Uses 24-bit A/D converter. Refer to Table: I.S.Thermocouple sensor type specifications |
| Calibration | None required |
| Cold Junction Compensation (CJC) accuracy | ±0.7 °C |
| Cold Junction Compensation range | -40 °C to 85 °C |
| Temperature drift | 0.03 °C /°C |
| Open sensor detection | Yes |
| Channel isolation | Galvanically isolated according to EN 60079‐11, voltage peak value 375 VDC. |
| Input power requirements |
+24 VDC input power: ±10% at 23 mA maximum |
| CHARM heat dissipation | 0.60 W |
Note
In the 25 °C reference accuracy column in the following table, total error is made up of the 25 °C reference accuracy value, plus the CJC accuracy value, plus the sensor accuracy value.
| Sensor types | 25°C reference accuracy | Temperature drift | Nominal resolution | Full scale | Operating range |
|---|---|---|---|---|---|
| B |
±2.50 °C ±1.70 °C |
±0.07 °C/°C ±0.05 °C/°C |
~0.024 °C | 0 to 1820 °C |
250 to 400 °C 400 to 1820 °C |
| E | ±0.60 °C | ±0.03 °C/°C | ~0.018 °C | -270 to 1000 °C | -200 to 1000 °C |
| J | ±0.70 °C | ±0.03 °C/°C | ~0.022 °C | -210 to 1200 °C | -200 to 1200 °C |
| K | ±1.20 °C | ±0.05 °C/°C | ~0.025 °C | -270 to 1372 °C | -200 to 1370 °C |
| N | ±1.10 °C | ±0.04 °C/°C | ~0.024 °C | -270 to 1300 °C | -200 to 1300 °C |
| R | ±1.70 °C | ±0.06 °C/°C | ~0.028 °C | -50 to 1768 °C | -50 to 1767 °C |
| S | ±1.90 °C | ±0.07 °C/°C | ~0.028 °C | -50 to 1768 °C | -50 to 1767 °C |
| T |
±0.70 °C |
±0.02 °C/°C |
~0.01 °C | -270 to 400 °C |
-200 to 400 °C |
| ±100 mV | 50 µV | ±2.5 µV/°C | ~0.0031 mV | -100 to 100 mV | -100 to 100 mV |
| ±50 mV | 40 µV | ±1.7 µV/°C | ~0.0015 mV | -50 to 50 mV | -50 to 50 mV |
| ±20 mV | 20 µV | ±0.8 µV/°C | ~0.0006 mV | -20 to 20 mV | -20 to 20 mV |
