Channel Value Difference Too High

What does 311 mean?

This error indicates that the difference between redundant or monitored input channel values has exceeded the configured tolerance window. This suggests a discrepancy in sensor readings, a calibration issue, or a wiring fault affecting one of the channels, compromising redundant safety monitoring.

• One of the redundant sensors has drifted out of calibration, providing a reading significantly different from its counterpart.
• Mechanical misalignment or damage affecting one sensor, causing it to read incorrectly compared to the other.
• Significant electrical noise or interference specifically affecting one of the input channels, leading to erratic readings.
• Faulty wiring (e.g., high resistance, intermittent connection) on one channel, causing a perceived signal deviation.
• The configured 'Value Difference Tolerance' parameter (e.g., P8-15) is set too narrow for the application's normal operating variations.

Click steps to track your progress.

1. 1

   1. Compare the raw signal values of both redundant input channels (e.g., Channel 1 and Channel 2) directly at the sensors.

2. 2

   2. Perform a calibration procedure for both sensors according to manufacturer specifications.

3. 3

   3. Inspect the physical mounting and alignment of both sensors for any discrepancies or damage.

4. 4

   4. Measure the voltage/current signal at the I/O module's input terminals for both channels and compare.

5. 5

   5. Review and potentially increase the 'Value Difference Tolerance' parameter (e.g., P8-15) to account for expected variations.