An option to disable the halting popup “Modbus Exception” when reading or writing to a Modbus TCP server from a UR program.
When reading or writing to a Modbus TCP server device from within a UR program, using the Installation->Fieldbus->Modbus TCP feature, the UR program will halt with a popup whenever the Modbus server device responds with “MODBUS EXCEPTION CODE 0x06 - SERVER BUSY”.
The UR program flow is halted and the user has to tap “OK” on the teach pendant to continue the program.
The Modbus exception 0x06 is part of the Modbus standard, and is intended to signal a temporary inability of the device to respond, which can be resolved by sending the request again.
It would be useful to have an option to ignore this exception code and allow the UR program flow to continue, especially in the context of cyclical requests set up via the Installation->Fieldbus->Modbus TCP feature.
For reading functions, when encountering the exception, the destination variable would remain unchanged from the previous value. For writing functions, no action is needed (but no popup would be shown) because there is no return value to check.
At the moment, it is impossible to incorporate Modbus TCP communication in a UR program, if the Modbus TCP Server device ever responds to the UR with “MODBUS EXCEPTION CODE 0x06 - SERVER BUSY”.
The UR program halts with a popup and disrupts the flow.
In the context of cyclical requests set up via the Installation->Fieldbus->Modbus TCP feature, where data is updated frequently, a user might prefer to ignore this exception code and retain the last value without modification, instead of halting the program.