Open Wire Detection Fault

What does I:Chxx.Fault mean?

This fault indicates that an input wire has become disconnected from the module channel (xx). It occurs in various operating modes: Current, Voltage, RTD, and Thermocouple. When this fault is active, the I:Chxx.OpenWire tag is also set to 1, signifying the open circuit condition. This condition directly affects the accuracy and reliability of analog input measurements for the respective channel, potentially leading to incorrect process control actions.

• Physical disconnection of the input wire from channel xx terminals or at the sensor transducer.
• For Current (mA) mode: Input signal level dropping below 100 μA.
• For Voltage mode: Input signal value reaching the full scale of the configured input range.
• Broken sensor wire or cable leading to channel xx for RTD or Thermocouple applications.

Click steps to track your progress.

1. 1

   Visually inspect the physical wiring connections at the module terminals for channel xx and at the sensor/transducer for any disconnections, loose terminals, or damage.

2. 2

   Measure the input signal at channel xx terminals for Current (mA) mode — verify it is above 100 μA.

3. 3

   Measure the input signal at channel xx terminals for Voltage mode — verify it is within the configured input range and not at the full-scale limit.

4. 4

   For RTD or Thermocouple modes, perform a continuity test on the sensor wiring connected to channel xx to identify breaks.

5. 5

   Check the module configuration in the Logix Designer software to confirm that the "Open Wire Detection" feature is correctly enabled or disabled as required for channel xx (refer to page 100 for configuration details).