Overview
The Honeywell 8C-PAIMA1 51454470-175 reads temperature signals from thermocouples (TC) and resistance temperature detectors (RTDs) for industrial control systems. It supports remote cold-junction compensation for thermocouple measurements. In addition, the module offers second process variable (PV) scanning, configurable open thermocouple detection (OTD) protection, and temperature point expansion in increments of 16 points.
Key Features
- TC and RTD inputs: Accepts signals from thermocouples and resistance temperature detectors to measure process temperature.
- Remote cold-junction compensation: Supports reference-junction temperature correction for thermocouple measurements.
- Second PV scanning: Supports a second process variable scanning function with OTD protection.
- Configurable OTD protection: Allows users to configure open thermocouple detection according to supported system settings.
- 16-point expansion increments: Supports adding temperature points in increments of 16.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 8C-PAIMA1 51454470-175 |
| Spare Model | 51454473-175 |
| Brand | Honeywell |
| Product Type | Low-Level Analog Temperature Input Module |
| Input Types | Thermocouple (TC) and RTD |
| Voltage Rating | 24 VDC |
| Module Current Rating | 120 mA |
| Channel Bandwidth | 0 to 4.7 Hz (-3 dB) |
| Nominal Input Range (TC Only) | -20 to +100 mV |
| Maximum Normal-Mode Continuous Non-Damaging Input (TC) | -10 to +10 V |
| Maximum Normal-Mode Continuous Non-Damaging Input (RTD) | -1 to +2 V at 100 mA |
| Gain Error (-20 to +100 mV Range) | 0.050% of full scale maximum |
| Long-Term Drift | 500 ppm |
| Input Impedance (TC Only) | Megohm range at DC; exact value requires verification |
| CMRR at 50 or 60 Hz | 120 dB minimum |
| Channel-to-Channel Voltage, DC to 60 Hz | +/-33 VDC or VAC RMS |
| Channel-to-Shield Voltage, DC to 60 Hz | +/-250 VDC or VAC RMS |
| NMRR at 50/60 Hz | 60 dB minimum |
| Manufacturer | Honeywell |
| Country of Origin | USA |
| Estimated Shipping Dimensions | 19 x 18.7 x 6.5 cm |
| Weight | 0.46 kg |
| HS Code | 8537101190 |
Temperature Measurement and Signal Handling
The module reads low-level signals from thermocouples and RTDs. Thermocouples generate a small voltage that varies with temperature, while RTDs use changes in electrical resistance. Therefore, the input configuration must match the sensor type and its measurement requirements.
The specified thermocouple input range is -20 to +100 mV. Meanwhile, the channel bandwidth of 0 to 4.7 Hz (-3 dB) describes the frequency response of the input channel. This specification helps engineers assess its suitability for temperature signals that change over time.
Cold-Junction Compensation and OTD Protection
Thermocouples require cold-junction compensation to account for the reference-junction temperature. The module supports remote cold-junction compensation, which helps the control system interpret thermocouple signals correctly.
In addition, the module supports second PV scanning with configurable OTD protection. Open thermocouple detection helps identify an open circuit in a thermocouple input. However, the available specifications do not define the detailed OTD settings or the operating conditions for second PV scanning.
Accuracy and Electrical Limits
The module specifies a maximum gain error of 0.050% of full scale over the -20 to +100 mV range. It also lists long-term drift of 500 ppm. Together, these values help engineers assess measurement performance over time, although they do not establish the total measurement error under every operating condition.
The module provides a minimum common-mode rejection ratio (CMRR) of 120 dB at 50 or 60 Hz and a minimum normal-mode rejection ratio (NMRR) of 60 dB at 50/60 Hz. These figures describe its ability to reject electrical interference at the specified frequencies. The listed non-damaging input limits define electrical limits, not recommended measurement ranges.
Frequently Asked Questions
Q: Which sensors does the Honeywell 8C-PAIMA1 support?
A: The module supports thermocouples (TC) and resistance temperature detectors (RTDs). Before installation, confirm that the selected input configuration matches the sensor type and its electrical requirements.
Q: Why does this module support remote cold-junction compensation?
A: Thermocouples require reference-junction temperature correction to determine the measured temperature accurately. Remote cold-junction compensation supports this correction for thermocouple measurements.
Q: What should engineers check before selecting this module?
A: Check the sensor type, input signal range, electrical limits, and required OTD configuration. Also, verify the spare model number and the system’s supported hardware configuration before ordering a replacement.
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