Arduino DUE VCU with analog and CAN control

[arber333]

One glitch i discovered with DUE...
Its internal pullup resistors are a joke. I have noticed that during driving sometimes a PP sense pin i use with internal resistor drops from 3V3 and it signals as if EVSE would be plugged in. This causes another pin to command relay to pull in the coolant pump and Notaus switch to disable the car!
Of course when this happens at 130km/h it is exciting . Luckily Lebowski has option to fully recover into RPM after chip reset.

Immediate solution for me was to add external 10K resistor to +3V3 plain. This resolved the glitch and i havent had any incident since.
But i urge you to inspect your boards for a solution as it is quite simple. Just scrape some of insulation near the PP pin on the 3V3 plain and solder 0805 resistor there as a pullup. See photos.

Location of pins on the front side

I schratched the layer to expose the copper on the underside where i have 3V3 plane

I soldered 10K resistor from the pin towards 3V3 plane

In future i will correct the design with V4.2 and add additional pullup resistors to all input pins.
https://github.com/arber333/Arduino-Due-CAN-shield
EDIT: I have fixed V4.2 with additional resistors 10K tied to 3V3 and specific pin. To have more freedom i put resistors even to those pins which are set with resistor divider to receive 12V input, just to leave some option of signal polarity. You dont need to populate all of them, just the ones you actually want to use.
I also fitted a set of 5 pins for inputs with 10K pullups onboard. It is getting crowded on the shield.
I will now work on V5 board version with CAN and LIN bus with 48pin sealed connector.

[900]

Did you see my previous post, current circuit on this board does work, relay and nmos for CP, I've tested and proof it already. This does 'waste' a relay for CP, FET doing that would be nice.

Hi, thanks for that. Would you share which components you populated on the shield for CP and proximity?

[900]

Immediate solution for me was to add external 10K resistor to +3V3 plain. This resolved the glitch and i havent had any incident since.
But i urge you to inspect your boards for a solution as it is quite simple. Just scrape some of insulation near the PP pin on the 3V3 plain and solder 0805 resistor there as a pullup. See photo.

Hi Arber, could you please attach this picture how to solve this pull up resistor issue? I am planning to use this shield to run my precharge, DCDC and HV contactors and it would be disastrous if my contactors were dropped during driving because of a glitch. Do you think it would be safe to run contactors with DUE and this shield or what would you recommend to prevent accidental contactor dop out during driving? At the moment until I get everything else sorted I run my contactors manually but that's quite a hassle to go through the procedure every time.

My recommendation for next shield version: make the shield longer than the Due board and add more relays with selectable signals to switch.

[arber333]

Hi Arber, could you please attach this picture how to solve this pull up resistor issue? I am planning to use this shield to run my precharge, DCDC and HV contactors and it would be disastrous if my contactors were dropped during driving because of a glitch. Do you think it would be safe to run contactors with DUE and this shield or what would you recommend to prevent accidental contactor dop out during driving? At the moment until I get everything else sorted I run my contactors manually but that's quite a hassle to go through the procedure every time.

My recommendation for next shield version: make the shield longer than the Due board and add more relays with selectable signals to switch.

Darn! I simply forgot sorry. Now i uploaded photos where you can see how i resolved this.
EDIT: I see you want to use DC contactor and precharge relay with DUE board. I would advise against direct connection. You could reliably use precharge function with DUE and even use DC contactor signal from DUE, but whenever DC contactor is activated you need to lock it with a latching relay or a relay pair.
I would recommend this action sequence:
1. Turn ON the key which brings 12V to precharge circuit and latching relay
2. After certain time precharge allows 12V pulse to DC contactor relay circuit.
Now this is DPDT relay that is wired to carry 12V from the key via one set of contacts to the coil, acting as latching relay.
This will keep your DC contactor active even if starting pulse is gone. You can use this with car starter circuit too.
3. To disconnect DC bus you simply return the key to the off position which will remove 12V altogether from the relay. In that case push to break button is not neccessary.

I am now making a redesigned board for V5 but not with DUE. Rather i selected DUE CORE board which has smaller profile. It also has space for EEPROM chip already on the DUE CORE. With it i can use simple plastic box from arduino with 24pin sealed connector. I am aiming on making it universal so it could be used to control Outlander or Nissan inverter and serve as a charger controler. I am also looking at simplifying Chademo controler by adding two relays to the board.
This should make the board universal like and simplify conversions further...
EDIT2: I am seeing my JK balancer speaks CAN communication at 250kbps contrary to ISA shunt which speaks at 500kbps. I will try to reprogram ISA shunt so i can use only one CAN line for this.

https://www.aliexpress.com/item/1005002 ... 1802NuF6Sw
http://www.inhaos.com/product_info.php?products_id=164

[900]

EDIT: I see you want to use DC contactor and precharge relay with DUE board. I would advise against direct connection.

Yes exactly, I also thought if direct driving HV contactor coils with due and the ULN would be a good idea so I had the exact same though if there has to be another board that due could give a signal to it and which wouldn't let go of the contactors in case of due malfunction while driving. However I had no idea latching relays existed. I have already programmed my Due to listen to CAN requests from inverter and respond with certain CAN messages that it expects but I engage my contactors manually prior to that. What I would like to do just insert a little bit of code so that Due would also send a signal to engage precharge and main contactors when it sees certain CAN messages from inverter. So how would you suggest to do that? What could that signal from Due be? My problem is I lack understanding in electronic circuits and diagrams. Those circuits that you uploaded are they readilly available or would need building? Would you explain in a bit more detail for a complete novice?

[arber333]

Yes exactly, I also thought if direct driving HV contactor coils with due and the ULN would be a good idea so I had the exact same though if there has to be another board that due could give a signal to it and which wouldn't let go of the contactors in case of due malfunction while driving. However I had no idea latching relays existed. I have already programmed my Due to listen to CAN requests from inverter and respond with certain CAN messages that it expects but I engage my contactors manually prior to that. What I would like to do just insert a little bit of code so that Due would also send a signal to engage precharge and main contactors when it sees certain CAN messages from inverter. So how would you suggest to do that? What could that signal from Due be? My problem is I lack understanding in electronic circuits and diagrams. Those circuits that you uploaded are they readilly available or would need building? Would you explain in a bit more detail for a complete novice?

Latching relay is nothing but 2x DPDT relays wired so first one can trigger itself and second one. Then it will keep connection untill 12V power is removed which will happen via car key. The simplest of methods i used in my Mazda back in 2013. Now with more sophisticated control however you can delegate DC contactor "turn on" to your inverter, however "turning off" will again be out of its hands since latching relay will turn off only when you remove 12V power.
Idea is for inverter to pull precharge signal in and after some time trigger DC relay. Then it can turn precharge relay off since its resistor is now bypassed. So you need two signals from inverter. I think your DUE is unnecessary for precharge. You need it for other tasks though. What kind of inverter do you use?

[900]

What kind of inverter do you use?

I use a not very common ~50 kw peak OEM inverter that I found how to control. I've analyzed the CAN log from original car and it seems that when inverter sends a CAN message requesting to enter run mode the original BMS then goes through the sequence enabling precharge contactor for a couple seconds then enters run mode and closes main contactor. So I thought I could get the DUE to listen for the request from inverter and go through the same sequence sending signals to close contactors. Because I already use a Due and need it to respond to inverter by sending certain messages so it can start. What would be your suggestion to that? If I understood correctly you're suggesting to just use a latching relay supplying 12V to it via turning ignition key to start position? Couldn't I do it via Due and your shield via ULN chip?

[900]

Latching relay is nothing but 2x DPDT relays wired so first one can trigger itself and second one. Then it will keep connection untill 12V power is removed which will happen via car key.

So which latching relay would you recomend? I have bunch of small 12V DPDT relays can I make a latching relay out of them?

[arber333]

Latching relay is nothing but 2x DPDT relays wired so first one can trigger itself and second one. Then it will keep connection untill 12V power is removed which will happen via car key.

So which latching relay would you recomend? I have bunch of small 12V DPDT relays can I make a latching relay out of them?

Most definitely yes. Or you can use a single relay with multiple contacts. Use the second sketch. And to break connection you simply remove 12V power from the key. Set one pair of contacts to loop back 12v to its coil. That should leave another contact to supply 12V towards DC contactor.

[900]

Most definitely yes. Or you can use a single relay with multiple contacts. Use the second sketch. And to break connection you simply remove 12V power from the key. Set one pair of contacts to loop back 12v to its coil. That should leave another contact to supply 12V towards DC contactor.

Looks like that's the same relay you use on your shield. So how would I modify the connections (where to cut traces and where to add new) for 2 of those relays on your shield to act as latching relays, or at least one of those to act as latching relays? I know you meant them to drive fans etc but I would want them to drive my contactors. Otherwise if I attach another relay it would be sort of dangling in there as there is nowhere to attach it not very secure.
I'm also thinking to use another contactor to enable dcdc with your code for a few minutes when the car sits idle, as I've noticed it discharges 12V battery rather quickly.

[arber333]

No those relays are meant to run charger cp and pumps and dcdc signal. They could be used to provide trigger signal and you can setup a relay somewhere i a car l with wire leading to it. But i would advise agaist this.
You can use another pin of the uln2008 chip. Either for the contactor and/or for precharge. You can change the code to react to "enable" input and start precharge and 2s later trigger dc contactor. There are several outputs to choose from all of them pull to gnd.

[900]

But i would advise agaist this.
You can use another pin of the uln2008 chip. Either for the contactor and/or for precharge. You can change the code to react to "enable" input and start precharge and 2s later trigger dc contactor. There are several outputs to choose from all of them pull to gnd.

Sorry I got a bit confused Didn't you suggest to use a latching relay earlier? So I was wondering if one of the relays (or both) can be turned into a latching relay. This particular shield is only going to drive contactors so I don't mind modifying it. I'll use another shield to pull in a cp.

[arber333]

Sorry I got a bit confused Didn't you suggest to use a latching relay earlier? So I was wondering if one of the relays (or both) can be turned into a latching relay. This particular shield is only going to drive contactors so I don't mind modifying it. I'll use another shield to pull in a cp.

I will draw you a sketch tomorrow...

[900]

I will draw you a sketch tomorrow...

Thank you, looking forward to automatic contactor control finally

[arber333]

Thank you, looking forward to automatic contactor control finally

Well, i dont know about automatic, but close...
See the file sketch.

You will notice i drew one DC contactor with precharge relay and resistor in parallel.
Precharge is run by one Nmos or NPN (ULN2008 ladder), so it can amplify relay up to 500mA.
DCDC contactor could very well be run in the same way, but i recommend you use at least 2 pins of ULN2008 chip in parallel for 1A draw power
Both pins are power neutral. This means they only sink power towards GND and dont care how much votlage is on the other side - up to some sane value...
Latching circuit is simply DPDT relay which uses one complement of its contacts to connect GND to its coil. With that the other side can be connected to 12V. When NPN pulls its collector to GND it will create a circuit through which its contact pair will keep relay latched. First contact pair will then show 12V to DC contactor and keep connection for the remainder of the drive.
If you want to break this you just need to remove 12V from innitial contact. This is why this pin needs to be fused and mechanically actuated. if you would just connect live 12V power you wouldnt be able to break contact at all!

EDIT: You can use "Enable" signal from key to signal DUE (enable input pin) to start precharge process. After 3s DC pin active condition will remove precharge pin and signal DCDC to start.
It can all happen on this condition.

[900]

EDIT: You can use "Enable" signal from key to signal DUE (enable input pin) to start precharge process. After 3s DC pin active condition will remove precharge pin and signal DCDC to start.
It can all happen on this condition.

I have a total of 8 contactors that I can use: 2 large Kilovacs with economisers for both HV+ and HV- and 6 that are only half the size without economisers I think. Both DCDC + and - have a small contactor each. I am just thinking what if I wire those 2 DCDC contactors directly to 12V after ignition? So every time ignition would come on DCDC would come on. Or is that not a good idea? You are proposing something similar aren't you? Precharge is needed for inverter only isn't it? So I could run precharge after dcdc had come on and when I'm starting the car (turning the key to start position)?
Now one thing I'm not sure how to achieve - since there are 2 HV main contactors and precharge resistor is only wired for HV+ does that mean I need to close HV- contactor at the same time I'm running precharge contactor? So in theory I need 2 latching relays then for both HV main contactors?

[900]

See the file sketch.

Thanks Arber I understood your schematic. Have a few questions still:
1. How do you connect input (com) to a relay on your shield? Do you route a wire to the com vias under the relay? I see that I can use that relay on your shield as a latching relay I will just loop ground to one of the normally open pins. If I need to cut the power to the relay could I use one of the transistors on your board to break that looped ground connection? I could use the second relay but I might need it to drive as a latching relay for the HV- contactor.
2. Do you leave your Due powered all the time? So far I have been only powering it when I was going to drive (12V supply after ignition). I was worried keeping it on all the time would decrease it's service life.
3. I measured my contactor power draw, large ones with enconomisers draw around ~0.3-0.4A, smaller ones around 0.4-0.5A too. I have 2 dcdc contactors to run both of them together draw around 0.86A. I'm thinking to use 3 ULN pins for both dcdc contactors and one pin for precharge. I would have one pin spare.
4. How do you suggesto to drive the HV- contactor?

[arber333]

See the file sketch.

Thanks Arber I understood your schematic. Have a few questions still:
1. How do you connect input (com) to a relay on your shield? Do you route a wire to the com vias under the relay? I see that I can use that relay on your shield as a latching relay I will just loop ground to one of the normally open pins. If I need to cut the power to the relay could I use one of the transistors on your board to break that looped ground connection? I could use the second relay but I might need it to drive as a latching relay for the HV- contactor.
2. Do you leave your Due powered all the time? So far I have been only powering it when I was going to drive (12V supply after ignition). I was worried keeping it on all the time would decrease it's service life.
3. I measured my contactor power draw, large ones with enconomisers draw around ~0.3-0.4A, smaller ones around 0.4-0.5A too. I have 2 dcdc contactors to run both of them together draw around 0.86A. I'm thinking to use 3 ULN pins for both dcdc contactors and one pin for precharge. I would have one pin spare.
4. How do you suggesto to drive the HV- contactor?

No! I strongly advise not to use DUE relay as a latching relay. It was not intended as such. Just make a contact fuse box and pull your wires from due there. Use the car key lock contacts to signal "enable" to due. You can use DUE relay to signal 12V to latching relay and you can use other DUE pins to start precharge like i made in the drawing. That is the natural way...

Yes, DUE is powered all the time and in the newer code i implemented watchdog. I have no way of telling if it works, all i can say it doesnt freeze .

If you want to use more ULN pins in paralell you can just command those pins in code OR you can use only one pin, put a glob of solder on parallel pins and cut the rest of traces...

Hm... good question. I dont use HV- contactor. I have fuse for that...
You could simply use another latching relay (remember, connection needs to be firmly established) which would use a +12V signal from OTHER DUE relay or even directly from KEY ignition. Remember! First you need HV- engaged, then you bring in HV+ across contactor through resistor for precharge to function. What you want is more complicated, but can be done with a good thought to ignition sequence. Put it to paper, it may help you.

[900]

No! I strongly advise not to use DUE relay as a latching relay. It was not intended as such. Just make a contact fuse box and pull your wires from due there. Use the car key lock contacts to signal "enable" to due. You can use DUE relay to signal 12V to latching relay and you can use other DUE pins to start precharge like i made in the drawing. That is the natural way...

But why not use a Due relay as a latching relay? Would it not be up to the amp draw? I already have a contactor box with all contactors wired to HV and I have already put the Due inside that box to the side further from HV lines and been driving like that for ~3 months now. Due is handling some CAN messages necessary to run the inverter so now I wanted to step up and handle contactors with it. I don't understand how Enable line on your shield works or how to write a code for it. But I could signal some Due pins high for ULN chip easy enough upon reception on certain CAN messages which would work the same way as you are suggesting with Enable pin. Since you're suggesting to drive precharge and dcdc contactors directly from the ULN2003 chip on your shield I thought why not also modify that relay on your shield into a latching one and drive HV+ contactor with it - would save me having another relay dangling in there. But if this is going to be risky I will see if I can find a larger DPDT relay somewhere. I also need to drive HV- contactor somehow - with another latching relay upon ignition?

[arber333]

No! I strongly advise not to use DUE relay as a latching relay. It was not intended as such. Just make a contact fuse box and pull your wires from due there. Use the car key lock contacts to signal "enable" to due. You can use DUE relay to signal 12V to latching relay and you can use other DUE pins to start precharge like i made in the drawing. That is the natural way...

But why not use a Due relay as a latching relay? Would it not be up to the amp draw? I already have a contactor box with all contactors wired to HV and I have already put the Due inside that box to the side further from HV lines and been driving like that for ~3 months now. Due is handling some CAN messages necessary to run the inverter so now I wanted to step up and handle contactors with it. I don't understand how Enable line on your shield works or how to write a code for it. But I could signal some Due pins high for ULN chip easy enough upon reception on certain CAN messages which would work the same way as you are suggesting with Enable pin. Since you're suggesting to drive precharge and dcdc contactors directly from the ULN2003 chip on your shield I thought why not also modify that relay on your shield into a latching one and drive HV+ contactor with it - would save me having another relay dangling in there. But if this is going to be risky I will see if I can find a larger DPDT relay somewhere. I also need to drive HV- contactor somehow - with another latching relay upon ignition?

Let me explain... i wouldnt trust DUE with anything more than providing starting pulse to a relay. That can be provided by the second relay on DUE board. If you want to latch something you need 1. a +12V pulse to start and 2. a removal of +12V or drain to release. If you want to use DUE to start latching relay that would be OK. So use 12V signal from DUE relay to latch your contactors. But i wouldnt explicitly trust it with release pulse. Its logic might succumb to EMI or simply coding problems. Also 12V is routed to relay on the DUE directly. The only way to release then would be to remove 12V power to DUE itself, not desirable option.
Story short, inverter life depends on it. Release needs to come from the outside at least that is my philosophy. You may try differently, i am just noting the possible shortcomings.

Enable line is sense input from the key 12V. DUE will sense active input via resistor divider and a host of functions need this signal for the "engine running" equivalent signal. If that signal would be missing for example AC compressor control wouldnt function, heater wont work and coolant pump wont start...

[arber333]

Ok last time you asked about a specific relay. I think it was DPST since action happens with dual output pins from a single point.
My circuit for latching...
Dont forget you need to signal pulse 12V to this relay into a contact which will then be latched to 12V.

[900]

Ok last time you asked about a specific relay. I think it was DPST since action happens with dual output pins from a single point.
My circuit for latching...
Dont forget you need to signal pulse 12V to this relay into a contact which will then be latched to 12V.

Hi, so you're suggesting to have ground permanently connected to contactor and be switching 12V to contactor with a relay? My thought is to connect a relay to 12v after ignition permanently then be turning ground to relay via ULN2003 chip. Then kill 12V with ignition switch which would remove power to latched relay.

I already tested this relay and it latches. My main concern after seeing your post was the reliability of this little automotive relay during longer drives since it would be holding main contactor. So you're saying it might heat up and stop working reliably? I think I will just use it for latching and holding dcdc contactors.
I was searching for those 24VAC coil relays and found them from finder, so I think for the peace of mind I will go with them. Like this one:

[900]

Ok last time you asked about a specific relay.

So I tested this 12vdc automotive relay and it indeed gets hot when left connected to 12v dc power. Just as you said. Although it holds contacts when hot I wouldn't feel comfortable using it for such an important task. Going to try 24vac relay now when I get one.

[900]

My circuit for latching...
Dont forget you need to signal pulse 12V to this relay into a contact which will then be latched to 12V.

Meanwhile why I still don't have a 24vac relay I wanted to try this 12vdc automotive one. I wired everything according to your drawing just that I swapped polarity because I'm using Due with your shield to latch it by ULN2003. I connected HV+ contactor to permanent 12v and I'm supplying ground via relay by pin 87b. 87 is looped to ground of the coil. Now when due supplies ground to the coil the relay latches and turns on the contactor. The problem is I cannot unlatch it by removing +12v from the relay coil. The HV+ contactor stays on! What am I not seeing here? Where does the HV+ contactor get the ground from after I remove 12v from the relay coil?

[900]

Also what about these relays? Would they be suitable?