- Software
- IQANdesign
-
Questions
0
MC42 PWM HS+LS output overload
Does the MC42 perform an active LS diagnostic on PWM HS+LS outputs during startup, even when the application function group is disabled? We receive a Critical Overload on C1:39 with a SPAL ABL321P PWM output. Delaying the physical connection of the PWM wire until after startup completely eliminates the fault.
According to the manual, Appendix B (page 122) states that the check for an HS or LS short to the battery during startup has no contact? Or am I misunderstanding this?
Yet it does happen....
Customer support service by UserEcho
Hello Jesse.
The "No contact" is the message you would receive in a system that has a MC4x with this problem.
What happens if you short HS or LS to battery is that during startup you will try to power the unit trough those (back ending).
We detect that during the startup and the unit will not start the application.
This is to prevent a short circuit on an output starting the unit when it is not intended.
If you have the PWMOUT channel in a disabled function group you should not be getting any messages regarding that channel at all.
Have you checked that the channel is in a function group that is disabled from the start?
Meaning that you do not have any delays either in a channel or with the calculation order or anything like that before it gets disabled.
Do also keep in mind that the PWM/COUT are in pairs, A/B, C/D and so on.
So if you get overload on A you also get it on B, because they share high side driver.
But should still not get a error message if a channel is in a disabled group.