Discussion and questions related to the course Practical Motorsport Wiring - Professional Level
Does anyone know how to get a half bridge system to work on the AIM PDM?
You don't get a lot more than this diagram to help you. I am setting up the wiper system
What have you tried? The PDM support is only in the Race Studio 3 Beta Software currently, so I haven't played with it much. Have you looked at the software?
What are you confused about?
I have the Race Studio 3 Beta Software downloaded however the set up in Race Studio 3 looks very similar to those for other outputs. Its not clear how to utilize the half bridge function for wipers.
It shows in the attached instructions that it can be used to move the motor forwards and backwards however surely it just a simple forward motion required with a switch to earth as the wiper input it removed. The park is switched to earth when the wipers are in the park function.
Compared with the other PDM manufacturers it isn't very clear.
From my experience with PDMs and wipers, often you have two power outputs to the wipers, one for high speed and one for low speed. When you apply power to the high-speed wire, the low-speed wire actually supplies current (or "back powers") the low speed output -- so your PDM needs special circuitry to deal with this. The Park signal normally just pulses each time the wiper is in the park position. To turn off/park the wiper, you switch to low speed, and leave it on until the park signal indicates the wiper is parked.
A half bridge output is normally part of a full-bridge pair can usually be driven with either positive or negative polarity, as opposed to normal outputs that can only be driven to positive (battery voltage). What the diagram you showed demonstrates is how to use a wiper system that has a servo motor and two park switches (one at each end). When one switch becomes active, the PDM will set the direction of the bridges to send the motor to the other switch, which changes the direction of the bridge and the process repeats.
So to help you... What wipers are you trying to control? What does the wiring for them look like? If replacing OEM wiring, have you monitored what happens to the various pins as the wipers are run slow, fast, and turned off (parked)? That will tell you what you need the PDM to do.
If you figure out how to setup the wipers can you post how you got it to work.