Our first step when troubleshooting an F7452 is usually not to suspect the drive itself at all, but to look at the more basic.
1. Mechanical condition, more important than you think
A lot of customers overlook the mechanical parts, especially after the unit has been running for a few years.
Some of the things we've seen include:
* Screws and guides become more resistant as they wear out.
* Quietly increased loads on axes.
* Slight crashes before, but still barely running.
* Motion "jerks” in a certain zone.
These problems are not noticeable at low speeds, but as soon as you accelerate or decelerate, the following error is immediately magnified, and the F7452 comes out. If the shaft is not smooth even if you play it by hand, it is useless if the driver is good.
2. Parameters have not been changed, but become a problem
F7452 is often associated with a parameter - the allowable value of the following error (P2546 is common on V90).
In some devices, this value is set "conservatively” during factory commissioning. At first there is no problem, but later: the acceleration is increased, the tempo is faster, the process is changed. As a result, the parameters are still stuck in a few years ago, naturally began to frequent alarms.
Here to say a word of truth: not let you brainlessly adjust the tolerance up, but to combine with the actual state of motion to judge. Adjusted too loose, the positional accuracy will be a problem; adjusted too dead, the equipment is not moving and stop.
3. Encoder and feedback signals, really "delicate”
This is a very common situation in our maintenance. On the surface of the machinery, everything is normal, the parameters have not moved, but the F7452 jumped out every now and then.
In the end, the problem is:
* Loose encoder plug.
* Feedback cable was pulled in the drag chain for a long time.
* The shielding was broken and there was a lot of interference in the field.
In this case, the motor is actually keeping up, but the feedback signal "seen” by the driver is not stable, so it will mistakenly think that the shaft is not keeping up.
4. Replaced the motor, but not re-tuned
This pit, people who have stepped on it understand. Motor replaced, the parameters directly copy the old; or mechanical structure changed, but the servo parameters remain in the original set.
The result is:
* Slight oscillation.
* Overshoot.
* Dynamic errors are instantly amplified.
The F7452 will show up when you least expect it.
5. Firmware versions, which are not entirely out of the question
This doesn't happen much, but it does happen. Some older firmware versions of the SINAMICS V90 are "sensitive” to following errors under certain conditions. If you have already checked the mechanics, parameters and feedback, it is not a waste of time to look at the firmware version.
