BECKHOFF CX9020 - Manual (Page 41)

Error handling and diagnostics
K­bus state
The K­bus status is saved in the state byte (see fig. K­bus interface “1”). If the value is 0 the K­bus is
operating synchronously and without errors. If the value is <> ”0” there may be a fault, or it may only be an
indication that the K­bus cycle is longer than the task, in which case it would no longer by synchronous with
the task. The task time should be faster than 100 ms. We recommend a task time of less than 50 ms. The K­
bus update time typically lies between one and five ms.
Bit 0 = K­Bus error
Bit 1 = terminal configuration has changed since the start
Bit 2 = process image lengths do not match
Bit 8 = no valid inputs (yet)
Bit 9 = K­bus input update not yet complete
Bit 10 = K­bus output update not yet complete
Bit 11 = watchdog
Bit 15 = acyclic K­bus function active (e.g. K­bus reset)
If there is a K­bus error, this can be reset via the IOF_DeviceReset function block (in the TcIoFunctions.lib).
CX9020 41 Version 1.1