9400 Servo PLC from firmware version 05.00.10.00
Response of the new version?
The setpoint speed of the profile generator is limited to the maximum value range +/-2^31. A setpoint step-change cannot occur anymore.
Which products are affected?
9400 HighLine with a firmware version < 11.00.10.00
9400 ServoPLC with a firmware version < 05.00.10.00
What happens?
When the acceleration/deceleration is reduced during a positioning process, on the basis of the parameters set a speed setpoint is reached which exceeds the limitation C909/1+2 (upper and lower speed limit value). With the Lenze setting C909/1=175% and C909/2=-175%, the speed setpoint is limited upstream to the speed controller.
If the speed setpoint continues to increase according to the parameters "acceleration/deceleration", and "S-ramp time" (>C909), a following error builds up.
Typically, the following error monitoring will take effect now and stop the drive.
The response may occur in the positive and negative direction of rotation.
If the following error monitoring is not active, the following response can be observed:
During a positioning process, the drive accelerates very slowly until the limitation in C909 is reached, remains at this speed limitation for a while, and the speed setpoint then changes its sign within one task cycle (e.g. 1ms). This setpoint step-change causes a jerk at the drive. When the drive continues running, the same response occurs at the negative speed limit.
When does the problem occur?
If a current acceleration value with a much greater smoothening (combination of deceleration and S-ramp time) is reduced than has been used before when the acceleration was established starting from zero speed.
Size:
Example:
Acceleration/deceleration ratio of 180/1; S-ramp time 100ms
No following error monitoring!
Diagnostics options?
See oscillogram example.
Short-term measures/recommendations?
Only set acceleration/deceleration ratios < 150/1 or S-ramp time=0.
Evaluation:
The speed setpoint step-change from the positive to the negative limit value typically does not occur, since a following error monitoring in position-controlled drives is common. This monitoring takes effect before there is an overflow in the setpoint. The smoothening required for the occurrence is only to be expected in the case of very untypical profile parameters.
