# Can I connect Curtis I/O ground to vehicle ground?



## frodus (Apr 12, 2008)

Which curtis?
Which BMS?


----------



## EV2012 (Oct 13, 2012)

Oh, sorry, I forgot to mention. 
It is the Curtis AC motor controller 1238R-7601.
The BMS is my own. So the ground signal on the input is connected to vehicle ground.


----------



## frodus (Apr 12, 2008)

Where did you get your controller/motor from? HPEVS?

If yes, then What software version is the VCL? Anything over 5.0 should support pin 2 tachometer output.
http://hpevs.com/Site/images/jpeg/S...1236-1238/auto1234-1236-1238_500-512_Reva.pdf
here's the software setup manual:
http://hpevs.com/Site/images/jpeg/instructions/Program%20Instructions%20REV%20A%205.00-5.09.pdf

The Curtis IO is NOT isolated on the 1238, 1238R. This means all of those signals reference pack negative. If your BMS is not isolated on that incoming signal and between its battery references, then it can (and likely will) cause an isolation issue. This may fry either your BMS, or your curtis IO board. 

What I'd do, is get a cheap optocoupler, drive the LED side via the Curtis, and interface the other side into your BMS. Wire the LED side to pin 2 of the curtis and set up the menu's on the curtis correctly.


----------



## EV2012 (Oct 13, 2012)

Thank you very much, that helps me a lot!
Controller was from Tecknowledgey. The motor is from a german supplier.
So I had only the Curtis manual. Didn´t know that there are existing other documents too.

So I will check the wiring, which is not completely finished and then the software.
I don´t know what software version it is. Because the controller is not running yet. 

I think it is not V5.0 because the controller is already 1,5 years old.
If it is not higher than V5.0 can it be updated?


----------



## frodus (Apr 12, 2008)

Ok, so your controller WILL NOT have HPEVS code in it. Tecknowledgey doesn't have access to HPEVS-written VCL. HPEVs wrote code that utilizes pin 2 as an output of motor RPM. I think you'll have to get an opto to interface to the actual encoder. Be careful it doesn't interfere with the existing encoder.

Have you run the controller yet?

Do you have a PC programming cable?


----------



## EV2012 (Oct 13, 2012)

The controller is not running yet, I am just wiring it.
I have the handheld programmer 1313.


----------

