Plausibility check
The plausibility check of the input signals serves as an extended diagnosis to detect interference signals and to identify and suppress the step changes in the counter value caused by them.
Functional principle of the plausibility check
The square wave signals of an incremental encoder with track A and B are phase-shifted by 90°. This means that only certain transitions in the signal curve are permitted or “plausible”, e.g. with a rising A-edge the signal on track B cannot also rise.
The plausibility of the signal sequence is checked in the terminal. If invalid signal transitions occur, these are detected and displayed accordingly if plausibility detection is activated.
Plausibility check sequence
- The plausibility check can be enabled via index 0x80n0:21 “Enable encoder plausibility check”
- If a plausibility error is detected, it is displayed as follows:
Error diagnosis | Description |
|---|---|
DiagMessage, | Encoder plausibility error (channel n) |
0xA0n0:13 | The error counter is incremented when a plausibility error is detected. |
0x60n2:0E | The associated TxPDO data are not valid. |
The plausibility error counter can be reset as follows:
- Transition from PREOP to OP
or
- Enter the following in the command object in Index 0xFB00:01 “Request”
0xFB00:01 “Request” | Description |
|---|---|
0x9151 | Sets the internal error counter 0xA000:13 “Encoder plausibility error counter” for channel 1 to zero |
0x9161 | Sets the internal error counter 0xA010:13 “Encoder plausibility error counter” for channel 2 to zero |