BUS-LED 5-1
Maximum input data length exceeded (Fault code 5, argument 1)
Wago · Modular I/O System PROFIBUS DP
What does BUS-LED 5-1 mean?
The total length of input data configured for the Fieldbus Coupler surpasses the maximum allowed limit (128 bytes, or 244 bytes from SW 03 onwards). This suggests that too many input modules are connected or their input data structures are excessively large, overwhelming the coupler's capacity.
Common Causes
- The number of connected input modules exceeds the coupler's maximum data capacity
- Total configured input data length is greater than 128 bytes (or 244 bytes for SW 03+ firmware)
Repair Steps & Checklist
Click steps to track your progress.
- 1
Switch off the supply voltage of the coupler.
- 2
Remove some I/O modules from the node to reduce the total input data length.
- 3
Switch the supply voltage on again to restart the coupler.
Verified technical data. Last updated: March 2026
Related Faults
Source: Wago Modular I/O System PROFIBUS DP