Which products are affected?
EVS93xx-EI (Servo PLC, software version <2.3)
EVS93xx-ET (Servo PLC, software version <2.3)
What happens?
The position value may deviate by 20 to 30 increments from the correct value (reference: 65536 inc/rev).
The input variable MCTRL_dnPos_p of MCTRL system module sometimes indicates another numerical number (difference: 20 to 30 increments) if the controller has been switched off and on again although the motor has not been moved.
When does the problem occur?
The actual value (position) is sporadically (approx. 1/10) not initialised correctly in case of absolute value encoders.
If it has been tried several times to switch on the device the initialisation value deviates sporadically by 20 to 30 increments (reference: 65536 inc/rev).
Possible diagnostics?
The value of the system variable MCTRL_dnPos_p can be saved before the PLC is switched off when using a retain variable. After switching on the PLC the saved value of the retain variable is compared to the actual value of the system variable. Although the motor has not been moved the two variables may differ by 20 to 30 increments.
Short-term measures/recommendations?
None.
Evaluation:
The deviation observed will not affect most of the applications since the deviation in the initialisation value of 20 to 30 increments (reference: 65536 inc/rev) is very small.
