8400 TopLine: FW version = 13.00.00.00
Response of the new version?
The position information is generated correctly, even if disconnection has taken place at a position change > 32767inc/ms.
Which products are affected?
8400 TopLine: FW version up to 12.01.00.00
What is the response?
After a mains failure, the current position in the inverter no longer matches the actual machine position. The ‚Reference known' status, however, remains set.
When does the problem occur?
If the encoder signal for the generation of the position in the MCK features a position change of more than 32767in/ms when the control card supply is switched off. In this case, a memory providing the increments > 32767 is not saved safe against mains failure quickly enough. Therefore, when the supply voltage returns, some of the position information required for reconstructing the current position is correspondingly missing.
This case can practically only occur if the position encoder is not mounted on the motor shaft. Systems with linear encoders such as laser encoders, bar code encoders, or Bowden wire encoders can potentially be affected.
Diagnostics options?
The maximum position change of encoders at X8 can be recorded via the variable LS_MultiEncoder.nSpeedAct_v at maximum machine speed.
In the case of values ≥ 32767inc/ms, the response can potentially occur during a mains failure.
Short-term measures/recommendations?
With linear encoders, it might be possible to avoid position changes ≥ 32767ic/ms by an appropriate parameter selection.
Evaluation:
The reference to the actual machine position is lost. In the case of position-based movements, the expected actual machine positions are not approached. Software limit position monitoring functions do not respond as expected.
It is very unlikely that the response occurs. In the course of typical tests during commissioning, the response will probably not be detected.
