Introduction
Use this guide to troubleshoot carton spacing issues at the Gapper on sorter systems. It covers symptoms such as cartons running too close together, Gap Errors on the sorter, and cartons being diverted to the Recirculation line. This article is intended for maintenance technicians and support engineers working in distribution center conveyor environments.
Issue description
When the Gapper conveyor is not creating enough separation between cartons, the sorter may detect Gap Errors and divert cartons to Recirculation. In many cases, encoder feedback is healthy and the issue is related to Gap Optimizer tuning rather than a hardware failure.
Signs
Cartons running too close together at the Gapper
Gap Errors appearing on the sorter
Cartons being diverted to the Recirculation line
Basic troubleshooting steps
Log into the CP6A_Merge PLC and review the Gap Optimizer settings.
Check encoder feedback for the Gapper conveyor, such as M706.
Verify that PPI values appear normal.
Test the encoder by unplugging it and confirming that encoder counts reset as expected.
Diagnostic tools/resources
CP6A_Merge PLC access
Gap Optimizer screen or configuration view
Encoder status points, including M706
Pontem KPI Dashboard
Advanced troubleshooting steps
Step 1: Confirm encoder health
Review the encoder feedback for the Gapper conveyor in the CP6A_Merge PLC. If the encoder counts behave normally and reset correctly when the encoder is unplugged, the encoder is likely healthy and not the root cause of the gap issue.
Step 2: Focus on Gap Optimizer tuning
If encoder feedback is healthy, adjust the Gap Optimizer Target Gap value. Increase the Target Gap incrementally with site approval. For example, change the value from 9.0 to 11.0, then to 12.0 if needed.
Step 3: Monitor system response
After each adjustment, monitor the system for approximately 15 minutes. Observe carton spacing throughout the sorter to confirm whether the gap is improving and whether Gap Errors are decreasing.
Step 4: Confirm expected recirculation behavior
Side-by-side cartons may still divert to Recirculation. This is expected behavior and does not necessarily indicate a new fault if overall spacing and Gap Error rates are improving.
Verification
Review the Gap Error rate in the Pontem KPI Dashboard before and after the Target Gap adjustment.
Confirm the Gap Error rate decreases after the Target Gap is increased.
Have the maintenance team confirm improved carton spacing at the sorter.
Contact support
If the issue continues after encoder verification and Gap Optimizer tuning, escalate the case to support engineering with the PLC observations, encoder test results, Target Gap values used, and Pontem KPI Dashboard screenshots.
Additional information
Always make configuration changes with site approval and follow local maintenance procedures. Use this guide as a reference for resolving Gapper carton spacing issues and Gap Errors on sorter systems.
Disclaimer
This guide is intended for trained personnel familiar with sorter and conveyor controls. Use discretion when applying adjustments, and follow site safety and change-control requirements before making system changes.