Question:
How does the position controller 9300EP react in a changeover positioning (final speed not zero) if the target position is close to the limit position (software limit) and will be overrun safely in the next program set (PS)?
Answer:
The taget position of the first PS is approached and the final speed is reached in the target (if the path is not too short), before the system changes to the next PS.
In the next PS the limit positions of the new target are checked. If they are not within the limits the monitoring of limit positions P04 or P05 is released and the drive is immediately braked with Amax.
During reversing, the limit positions can be overrun for a short term without releasing the monitoring of the limit positions P04 or P05, if the following requirements are met:
- The target position of the first PS with final speed is close to the limit position.
- The target position of the following PS is in the opposite direction.
- The limit positions can be overrun particularly if the brake path is long.
Example:
Position limit positive: 102 units
- PS1: target position = abs 100 units, Vend = Vtravel = 100 %
- PS2: target position = rel -30 units, flat ramps, so that the brake path is more than 2 units.
If, in individual cases, overrun of the limit positions is not acceptable, hardware limit switches must be used to avoid overrunning.
