Muting Discrepancy Error - Muting Group 1

What does FB MUTING Bit 0 mean?

A discrepancy has been detected in muting input group 1 (e.g., MuteIn1/MuteIn2) within the FB MUTING function block. This means the redundant muting sensors (e.g., light barriers) are not switching synchronously or are reporting different states, which can compromise the safe muting function, potentially leading to an unsafe bypass of a safety device. This triggers a safety stop.

• Misalignment of one or both muting sensors in group 1 (e.g., MuteIn1, MuteIn2) causing inconsistent signal detection.
• Accumulation of dirt, dust, or debris on the lenses of muting sensors MuteIn1 or MuteIn2.
• Electrical wiring fault (e.g., loose connection, intermittent open circuit) on one channel of muting input group 1.
• External light interference or reflective surfaces causing spurious triggering or blocking of a muting sensor.
• Sensor hardware failure of MuteIn1 or MuteIn2, leading to incorrect switching states or delayed response.

Click steps to track your progress.

1. 1

   1. Visually inspect and realign both muting sensors (MuteIn1, MuteIn2) in group 1, ensuring their optical axes are perfectly aligned and indicators are green.

2. 2

   2. Clean the lenses of MuteIn1 and MuteIn2 using a suitable optical cleaner and soft cloth.

3. 3

   3. Use a multimeter to verify the output signal (e.g., 24VDC or 0V) from MuteIn1 and MuteIn2 directly at the sensor and at the safety input terminals (e.g., X1.1, X1.2) while actuating.

4. 4

   4. Check for stable 24VDC power supply to both muting sensors in group 1; measure voltage at the sensor's power terminals.

5. 5

   5. Access the safety PLC diagnostics to check the raw input states of MuteIn1 and MuteIn2 for consistent simultaneous switching.