Product Overview
The Yokogawa AAR181-S50 is a 12-channel isolated RTD input module designed for precise temperature measurement in industrial automation systems. This module accepts Pt100 3-wire RTD signals per IEC751 and JIS C1604 standards, delivering reliable data for process control. With a ±5 V allowable input voltage and a withstand voltage of 1500 VAC between input and system, the AAR181-S50 ensures robust isolation and safe operation in harsh environments.
Technical Specifications
The table below lists key performance parameters of the Yokogawa AAR181-S50. All values are sourced directly from the product datasheet.
| Parameter |
Value |
| Number of Input Channels |
12, isolated |
| Input Signal (RTD) |
Pt100 (3-wire), JIS C1604:1997, IEC751:1995 |
| Allowable Input Voltage |
±5 V |
| Withstanding Voltage (Input to System) |
1500 VAC for 1 minute |
| Input Resistance (Power ON/OFF) |
2 MΩ or larger |
| Accuracy (RTD) |
±120 mΩ |
| Allowable Total Resistance of Signal Source Plus Wiring |
40 Ω or less (per wire) |
| Measurement Current (RTD) |
1 mA |
| Temperature Drift (RTD) |
±120 mΩ /10 °C |
| Data Update Period |
1 s |
| Burn-out Detection Time |
60 s (all channels settable) |
| Maximum Current Consumption |
450 mA (5 V DC) |
| Weight |
0.2 kg |
| External Connection |
Pressure clamp terminal |
Industry Applications
The Yokogawa AAR181-S50 excels in applications requiring precise, isolated RTD temperature measurements. Common use cases include chemical processing, power generation, and refinery operations where accurate temperature data is critical for safety and efficiency. In dual-redundant configurations, the module’s isolation prevents ground loops and signal degradation, ensuring consistent performance. The 1-second update period suits slow-trend processes, while the burn-out detection (60 s) alerts operators to sensor failures, reducing downtime.
Installation Guidelines
Proper wiring is essential for accurate readings with the Yokogawa AAR181-S50. Use 3-wire Pt100 RTDs and ensure the wiring resistance per wire does not exceed 40 Ω. The signal cables for INA and INC must have identical resistance to maintain measurement accuracy. Connect the module using the pressure clamp terminals and verify the input voltage stays within ±5 V. For dual-redundant setups, note that the effect of allowable signal source resistance varies; consult the installation manual for precise adjustments.
Troubleshooting Common Issues
Common problems with RTD input modules often stem from wiring resistance mismatch or temperature drift. For the Yokogawa AAR181-S50, if readings appear erratic, check that the total wiring resistance is 40 Ω or less per wire. Temperature drift of ±120 mΩ/10°C can cause minor deviations; account for this in high-accuracy applications. If burn-out does not trigger, verify the setting is enabled and the detection time of 60 s matches your system timing. Always follow the specification that wiring resistance for INA and INC cables must be identical.
Selection Guide
When procuring the Yokogawa AAR181-S50, confirm your system requires a 12-channel isolated RTD module with Pt100 support. Verify that your controller accepts the 1 s update period and 450 mA current consumption. For reliable sourcing, choose PLC Source PRO – we stock the AAR181-S50 and other Yokogawa control system spares. Contact us for bulk pricing or technical support.