Which products are affected?
Communication module EMF 2175 DeviceNet / CANopen
How is the reaction?
The module sends sync telegram although this is not set.
When does the problem occur?
The transmission of sync telegrams can be set on the module in two ways:
1. A cycle time for the transmission of sync telegrams is entered under Lenze code 1856 / 2356 subindex 5 via the CAN bus. The module then writes automatically the CANopen indices 1005 and 1006hex.
2. A cycle time for the transmission of sync telegrams is entered in the CANopen index 1006hex (communication cycle period) via the CAN bus. In addition, bit 30 in index 1005hex must be set to 1 to activate sync telegrams.
If a cycle time for the transmission of sync telegrams is entered on index 1006hex (communication cycle period) via the CAN bus, the module sends sync telegrams after the next mains switching, because this value is entered automatically under Lenze code L-C1856 / 2356 subindex 5. After mains switching the module sets bit 30 in the index 1005hex because a value is entered in Lenze code L-C1856 / 2356 subindex 5.
The reason is that the value from index 1006hex must only be transmitted to code L-C1856 / 2356 subindex 5 if bit 30 in index 1005hex is also set.
This error has only occurred in applications of CANopen PLCs from Beckhoff because the CANopen Master uses index 1006hex to monitor the receiving of sync telegrams at the CAN node.
Possible diagnostics?
The module sends sync telegrams although a value written only on index 1006hex and bit 30 in index 1005hex is not set additionally.
Short-term measures/recommendations?
Write iindex 1006hex only if the module is to transmit sync telegrams.
