Unintended Input Signal (Noise)

What does UNINTENDED-INPUT mean?

The input module receives unintended input data, which is actually noise being interpreted as a valid signal. This can occur if the input response time is set too short, allowing transient noise pulses to activate the input, or if external electromagnetic interference affects the input lines.

• Input response time setting is too short, causing the module to register noise pulses as legitimate input signals.
• Excessive noise in the operating environment or generated by nearby devices.
• Improper installation practices, such as running power cables in close proximity to I/O cables, leading to noise induction.

Click steps to track your progress.

1. 1

   Increase the input response time setting via the module parameters (refer to Page 117 for 'Input Response Time Setting'). For example, change from 1ms to 5ms.

2. 2

   Prevent excessive noise by physically separating power cables from I/O cables during installation.

3. 3

   Connect surge absorbers to noise-generating devices (e.g., relays) and conductors sharing the same power supply to mitigate noise reduction measures.