I’m wanting to control a BMW active grille motor from a PMU 24. The motor has 3 wires which I believe are a common ground and then motor open and motor closed. I can’t seem to find out of they have limit switches built in so I’m working on the assumption that when the motor has hit its mechanical stop and the current starts to rise, this is what is used to cut power.
How would I program the logic for this in the PMU? I obviously don’t want it constantly trying to motor against the stop and tripping to overcurrent limit. I was thing something along the lines, once “motor close” current > xxxA it can’t be activated again until “motor open” current > xxxA.
I don’t think this motor works as u assume.
More likely it is:
ground/+12V/ activation signal(usually ground)
Disconnected it is fixed in one position. Giving the right signal to the activation pin moves it to the endstop → no need to do a current limitation by urselfe…logic is inside the motor.
Bit of a follow up on this and it looks like the actuator doesn’t have a switch pin to run the shutters. I’ve since discovered they work via LIN bus and there’s no way of controlling them without knowing how its programmed (the motor is some sort of 3 phase motor). I’ve found a similar unit which although still uses LIN bus it has a 2 coil stepper motor, so I was wondering if the PMU24 would have the capability to run the stepper motor directly trough some sort of PWM table?
Interessting…but i think it is quite easy to reverse engineer the LIN communication for such a simple device…especially if it just has two states. But yes u need to be a bit familiar with this communication stuff.
Anyhow…PMU has PWM outputs…so i think there is no problem with useing them directly for a motor.
The problem I have is I have no way of knowing what the messages/ commands are. If I had the car the actuator came off I could just attach a oscilloscope and command the motor to open/close and replicate the commands but unfortunately I don’t have the original codes to replicate.