Beckhoff EL6751 Documentation page 171

Error Description
0x1801 StartFieldbus: In equidistant operation, shift time + safety time + 2*PLL sync. time
must be greater than the cycle time
0x1802 StartFieldbus: Cycle time is too large
0x1803 StartFieldbus: Cycle time is too large
0x1804 StartFieldbus: Shift time is too large
0x1805 StartFieldbus: PLL sync time is too large
0x1806 StartFieldbus: Safety time is too large
0x1807 StartFieldbus: Cycle times shorter than 1 ms must be integral divisors of 1 ms
EL6751 Version: 3.5
Error handling and diagnostics
171