Wiper Motor, works but 1 little bug!

[Robbied]

Hi,

I have a PDM 32 wired to a BMW Mini wiper motor, the park switch comes into the PDM (on I/P 4) and the low/high speed use output channels 9 & 10 as per the documentation.

It works really well and I can cycle my keypad button from off-low-high-off really well...

...except, when the master switch is first turned on, the wiper motor cylces once! I am making an assumption that the PDM doesnt see the park switch straight away for some reason.

Is there a neat way to overcome this and ensure it doesnt cycle the motor each time the car is turned on?!

Thanks,

[David Ferguson]

Is the PDM constantly powered, or is it's power controlled by the Master Switch? Can you zip your PDM config and upload it? It's hard to guess....

[Robbied]

Hi,

Its powered from the master switch. Essentially the car is then 'on' and the keypad has an Ignition switch that does pretty much what you would expect.

.PDM attached

[adrian]

It looks like when the PDM first measures the voltage on the input pin for the park switch during start up it doesn't exceed the threshold and the PDM reads it as 'false' and the output is turned on.

Easiest way to fix it is to simply add a delay condition to the park switch in the output condition (see below). This delay will only apply when the PDM first powers up so it won't change the functionality of the wipers when they are operating normally.

One question, why do you have both the low speed and high speed outputs on when the wiper is in high speed mode?

[Robbied]

Many thanks, i'll try that delay next time I see the car.

To be honest, I did the wiper control on the bench quite a while ago. We are only now just coming around to commissioning the (almost) complete car and going through all these functions.

Its a good question about the low speed being on in both positions. Again i'll edit the high speed output and see if it still works correctly. Im a little reluctant to make lots of changes to the setup before i'm able to check each one as I go.

I don't do many PDM setups so not as proficient with the software as i'd like to be!

[adrian]

The main reason I say that is that pin 9 has additional circuitry to protect it when the wiper is running in high speed mode (which is why you have to use pin 9 and link it in the software to the output used for high speed).

I don't actually know what happens when you have both outputs set on so you are better off just turning the low speed off when the high speed is on.

[Robbied]

Well the delay on initial start up that you suggested works perfectly, now when powering up the car the wiper motor doesn't cylcle.

I made an update with a couple of other things that worked well so thats a success.

Now to update again with the low speed output switched off when high speed is on, as has been suggested. The customer has also asked if we can add an intermittent function as the first press of the keypad button, then it cylcles to low, then to high, then to off. Does this sounds like its possible?

[br21]

yes, intermittent no problem, I prefer to use functions for all that. You just need to choose if you want wiper in slow or fast mode while in intermittent. And then use Flash function for intermittent, with True time lets say 0,5s and False time depends how "intermittent" you want it, some 3s is usually good to start with.

[Robbied]

A little update, we switched off the low speed output while the high speed is on. And the system works as before.

Except now you can see the channel swap over in PDM monitor when switching between low and high speed settings. So, all good.

Thanks all!