MRP job release fails in cloud advanced planning-error 'resource lock conflict'

MES Honeywell MES
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1

When releasing jobs from MRP in the advanced planning module, I’m getting ‘Resource Lock Conflict’ errors for about 30% of job releases. The error message shows:


ERROR: Job release failed - Resource lock conflict
Job ID: MRP-2025-02341
Resource: CNC-MILL-03
Conflict Time: 2025-02-10 14:00:00

This happens even when the resource calendar shows availability. I’ve verified that CNC-MILL-03 has no active jobs scheduled for that time slot, yet MRP refuses to release the job. We’re running hm-2023.1 in a cloud deployment across two time zones (plant in CST, cloud instance in PST). Could this be related to time zone handling? The resource lock conflicts are blocking our production backlog and causing delays in getting jobs to the shop floor.

2

To manually refresh: Administration → Cloud Services → Cache Management → find ‘Resource Planning Cache’ → click ‘Clear and Rebuild’. This forces the MRP engine to reload all resource calendars, shift definitions, and availability rules. Takes 2-3 minutes to complete. Do this during low-activity periods as MRP job releases will pause during rebuild.

3

The MRP engine in hm-2023.1 cloud runs in the cloud instance time zone by default, which in your case is PST. So when it checks resource availability at ‘14:00:00’, it’s checking 14:00 PST (which is 16:00 CST). If your resource calendar shows availability from 06:00-15:00 CST, the MRP engine sees that as 04:00-13:00 PST, missing the 14:00 PST slot it’s trying to book. You need to configure time zone alignment in Administration → System Configuration → Regional Settings → MRP Time Zone Handling.

4

Resource lock conflicts in cloud MRP usually stem from calendar sync issues. Check Administration → Advanced Planning → Resource Calendars and verify that CNC-MILL-03’s calendar is properly configured with your plant’s time zone (CST). If the calendar is in UTC or PST while your MRP runs in CST, the availability windows won’t align correctly, causing phantom conflicts.

5

Carlos, I checked the resource calendar and it’s set to CST which matches our plant. However, when I look at the conflict time in the error (14:00:00), I’m not sure if that’s CST or UTC. Is there a way to see what time zone the MRP engine is using for its calculations?

6

Beyond time zones, resource lock conflicts can occur if there are pending calendar updates that haven’t synchronized. In cloud deployments, resource calendar changes can take 5-10 minutes to propagate to the MRP engine cache. If someone modified CNC-MILL-03’s calendar recently (added maintenance window, changed shift times), MRP might be working with stale data. Check Administration → Cloud Services → Cache Status and look for ‘Resource Calendar Cache’ - if last update is more than 15 minutes old, manually trigger a refresh.

7

Patricia, I found the MRP Time Zone Handling setting and it was set to ‘Use Cloud Instance Time Zone’. I changed it to ‘Use Resource Calendar Time Zone’ which should make MRP respect the CST settings on our resources. However, I’m still seeing some conflicts. Mark’s point about cache is interesting - how do I manually refresh the resource calendar cache?

8

Here’s the complete solution addressing resource calendar sync, time zone alignment, and resource lock conflict resolution:

Resource Calendar Sync Configuration: The root issue is multi-layered. First, ensure resource calendars are properly synchronized between your plant systems and the cloud MRP engine.

Navigate to Administration → Advanced Planning → Resource Calendars:

  1. Select CNC-MILL-03 (and other affected resources)
  2. Verify ‘Time Zone’ is set to ‘America/Chicago (CST)’
  3. Check ‘Calendar Source’ - should be ‘Cloud Synchronized’ not ‘Local Override’
  4. Review ‘Shift Definitions’ - ensure shift times are in 24-hour format with explicit time zone Example: Shift 1: 06:00:00 CST to 14:00:00 CST (not just 06:00-14:00)
  5. Under ‘Sync Settings’, set ‘Sync Frequency’ to 5 minutes for production resources
  6. Enable ‘Real-time Availability Updates’ - this pushes calendar changes immediately rather than waiting for scheduled sync

For resources showing conflicts, click ‘Validate Calendar’ button. This checks for:

  • Overlapping shift definitions
  • Missing break periods
  • Maintenance windows without proper exclusions
  • Daylight saving time transition gaps

Time Zone Alignment for MRP: Administration → System Configuration → Regional Settings:

  1. Under ‘MRP Time Zone Handling’, verify you’ve set ‘Use Resource Calendar Time Zone’ ✓
  2. Additional critical setting: ‘Time Zone Conversion Mode’ → set to ‘Explicit Conversion with Validation’ This makes MRP log warnings when time zone mismatches occur rather than silently using cloud instance time
  3. Enable ‘DST-Aware Scheduling’ - critical for avoiding conflicts during daylight saving transitions
  4. Set ‘Default Planning Horizon Time Zone’ to match your primary plant (CST)

Under Advanced MRP Settings:

  • ‘Resource Lock Duration’: Default is 30 minutes. If jobs frequently overrun, increase to 60 minutes to prevent overlapping bookings
  • ‘Lock Granularity’: Set to ‘Per Resource’ not ‘Per Resource Group’ - this prevents false conflicts when multiple resources in a group are available
  • Enable ‘Soft Lock for Planning’ - allows MRP to propose schedules even with minor conflicts, flagging them for manual review

Resource Lock Conflict Resolution: The ‘30% failure rate’ suggests systematic timing issues. Check these specific scenarios:

  1. Concurrent MRP Runs: Administration → Advanced Planning → MRP Execution History Look for overlapping MRP execution times. If multiple planners run MRP simultaneously, they compete for resource locks.

    Solution: Configure ‘MRP Execution Queue’ to serialize runs, or assign resources to specific planners

  2. Maintenance Window Conflicts: Administration → Resource Management → Maintenance Schedules Verify maintenance windows are excluded from available capacity. A common issue: maintenance scheduled in UTC but resources in CST

    For CNC-MILL-03, check if maintenance is scheduled around 14:00 - this aligns with your error timestamp

  3. Time Zone Boundary Issues: Your conflict time (14:00:00) is problematic because:

    • 14:00 PST = 16:00 CST (after typical shift end of 15:00 CST)
    • If MRP runs in PST but calendars in CST, there’s a 2-hour gap where availability windows don’t align

    Fix: Administration → Advanced Planning → MRP Configuration

    • Set ‘Planning Time Zone’ to ‘CST’ (matches plant)
    • Enable ‘Convert All Timestamps to Planning TZ’ - this normalizes all times before scheduling
    • Set ‘Time Zone Offset Warning Threshold’ to 1 hour - alerts when timestamps differ by more than 1 hour from expected

  4. Cache Refresh Automation: Don’t rely on manual cache clearing. Administration → Cloud Services → Cache Management:

    • Set ‘Resource Calendar Cache TTL’ to 5 minutes (down from default 15 minutes)
    • Enable ‘Auto-Refresh on Calendar Change’ - cache rebuilds automatically when calendars update
    • Set ‘Pre-fetch Resource Availability’ - loads next 48 hours of availability into memory for faster MRP execution

Validation and Testing: After configuration changes:

  1. Clear the resource planning cache (as Mark described)
  2. Run a test MRP release for a single job on CNC-MILL-03
  3. Check Administration → System Logs → MRP Execution Log for detailed timestamp information
  4. Look for entries showing: ‘Resource Available: CNC-MILL-03 from HH:MM:SS TZ to HH:MM:SS TZ’
  5. Verify the times shown match your expected CST availability windows

If conflicts persist:

  • Check for ‘ghost locks’ from previous failed releases: Administration → Advanced Planning → Active Resource Locks Clear any locks older than 2 hours
  • Verify your cloud instance regional settings: Administration → Cloud Services → Instance Configuration Ensure ‘Instance Region’ aligns with your primary operations (US-Central for CST plants)
  • Review MRP planning parameters: Some advanced planning algorithms pre-book resources during simulation phase, creating temporary locks Set ‘Release Simulation Locks After’ to 5 minutes instead of default 30 minutes

Expected outcome: Resource lock conflicts should drop from 30% to under 5% (some conflicts are legitimate - truly unavailable resources). Remaining conflicts should have clear explanations in the MRP log rather than mysterious time zone mismatches.