# DMOC Help



## sabahtom (Mar 1, 2011)

Try posting this on evtv.me forums.

They're more into the DMOC645, but there are a couple of guys there who've gone into the DMOC in this depth. They are busy though


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## CKidder (Dec 12, 2009)

It is possible that the voltage regulator on your digital board is messed up and causing things to fluctuate all over the place. I accidentally zapped the voltage regulator on a DMOC445 in the past. The first thing to try is to disconnect the direction switch and accelerator pedal from the DMOC and test them directly with a multimeter. The pedal should be a 5k pot. It won't (or shouldn't) go to either 0 or 5,000 ohms but will have a range of like 2000-3000 somewhere in the middle. I don't remember the exact values but it'll be something like 1000 - 3500 or something like that. The direction switch I believe should cleanly (basically no resistance) connect between wires - it should just be a switch.

Unfortunately it could be a lot of things. Try leaving that stuff disconnected and turn the DMOC on without an accelerator or direction switch. It will probably fluctuate with nothing connected but you could see if this behavior matches the current performance or not. It is possible that your cabling is just plain faulty somewhere and you aren't getting a signal through to the DMOC.


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## rclugnut (Aug 11, 2011)

CKidder said:


> It is possible that the voltage regulator on your digital board is messed up and causing things to fluctuate all over the place. I accidentally zapped the voltage regulator on a DMOC445 in the past. The first thing to try is to disconnect the direction switch and accelerator pedal from the DMOC and test them directly with a multimeter. The pedal should be a 5k pot. It won't (or shouldn't) go to either 0 or 5,000 ohms but will have a range of like 2000-3000 somewhere in the middle. I don't remember the exact values but it'll be something like 1000 - 3500 or something like that. The direction switch I believe should cleanly (basically no resistance) connect between wires - it should just be a switch.
> 
> Unfortunately it could be a lot of things. Try leaving that stuff disconnected and turn the DMOC on without an accelerator or direction switch. It will probably fluctuate with nothing connected but you could see if this behavior matches the current performance or not. It is possible that your cabling is just plain faulty somewhere and you aren't getting a signal through to the DMOC.



Thanks we'll try leaving those unplugged, it is not the wiring harness it has been checked manually and works perfectly with our other unit. 

sabahtom, Thanks i'll be sure to post this up over there.


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## sabahtom (Mar 1, 2011)

rclugnut said:


> sabahtom, Thanks i'll be sure to post this up over there.


Hi Rclugnut, it looks like evtv is here already so no need to post it there 

_It won't (or shouldn't) go to either 0 or 5,000 ohms but will have a range of like 2000-3000 somewhere in the middle. I don't remember the exact values but it'll be something like 1000 - 3500 or something like that._

Hi CKidder

My PB6 pot box does go from about 0 - 4900kohm if I remember correctly. I've only tested it twice on the DMOC, seems to work. 

The DMOC came preset with the regen to operate from 0 to 0.2 in CCShell, and the manual says it must be a 5k pot box. I assumed that to mean that from 5000-4000kohm it would do regen, then 4000-0kohm it accelerates. Is it possible that I could damage the DMOC if the range of the potbox is outside 1000 to 3500 or so? I hope this is still relevant to the topic.


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## CKidder (Dec 12, 2009)

sabahtom said:


> Hi Rclugnut, it looks like evtv is here already so no need to post it there
> 
> _It won't (or shouldn't) go to either 0 or 5,000 ohms but will have a range of like 2000-3000 somewhere in the middle. I don't remember the exact values but it'll be something like 1000 - 3500 or something like that._
> 
> ...


My recollection is that my PB6 box never went outside of 1000-3500 but I could be wrong. I'm nearly positive that it is correct for the pot to never go to the extremes. It should stay at least a little bit outside of 0 and 5000 so that the controller can detect open wires and shorts. You won't damage the DMOC if it gets values of 0 or 5000 ohms but if the normal range is too large then it will be difficult for the controller to properly fault if there is an issue with the potbox.


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## zaxxon (Jul 11, 2009)

CKidder, You are likely remembering the voltage range not the pot resistor range. I am not sure about the DMOC, but there are resistors inside the UMOC placed in the high side and low side in series with the connections to the pot. The resistors force the use of the 5K pot so the normal voltage rang is correct, and out of limits for opens and shorts can be detected.


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## rclugnut (Aug 11, 2011)

We have a 0-5k pot setup one is an azure unit another is aftermarket, in CCshell we have see the throttle values, usually from ~.1-.7 (ccshell doesn't give units) low to peak on both setups. We have set the throttle limits accordingly for fault detection for the working controller.

The unit that we are having issues with gives us random integers instead of holding a number in relation to the throttle position and or switch position. 

zaxxon suggested a grounding issue in my other thread which we'll try to chase down before finials start up (next week).


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