AEMNet CAN

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AEMNet CAN

Postby LT401Vette » Fri Nov 23, 2012 2:51 pm

Would it be feasible to enhance IOExtender or MS firmware to listen to AEMnet CAN messages and pass translate them to MS/Al CAN for megasquirt compatibility, or would MS CAN clobber the CAN network?

More specifically I was looking at the driveshaft dynometer. It appears the output from that is in AEMnet CAN only, the message definitions are in this doc:
http://www.aemelectronics.com/Images/Pr ... oshaft.pdf

At 1st I was looking to see if it had a voltage output, but it appears they went with CAN only, which you probably be much more accurate, so makes sense, but i want to be able to read the output in TS :)
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Re: AEMNet CAN

Postby jbelanger » Fri Nov 23, 2012 3:47 pm

It uses the correct bit rate and the 29-bit header so that is compatible with the MS/Al CAN. The problem is that the 3 message IDs used would mean messages from CAN ID 0 to CAN ID 2 in the MS protocol. So if there is a CAN device with CAN ID=2, there's a problem.

However, I have been thinking of using an SPI-CAN chip to extend the devices the IOx can talk to. And that was actually one of the devices I wanted to cover. The protocol is really simple but since I don't have access to one, it has been set aside. If you do have access to one, I will have a closer look at what I would need to make this work. If it works like I would like it to work, it would simply require the addition of an MCP2515 chip (available in a DIP package) and some wiring to the appropriate pins.

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Re: AEMNet CAN

Postby LT401Vette » Fri Nov 23, 2012 3:57 pm

Unfortunately the only way I have access to one is to buy one :(, but I would to have one in my own car :)

If you could set up this second chip with firmware that allowed a somewhat generic message definition, that could be nice for being able to log what ever data from CAN.
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Re: AEMNet CAN

Postby jbelanger » Fri Nov 23, 2012 4:08 pm

It should be possible to set it up such that a certain number of message IDs can be received and the raw data logged. And the bit rate should also be settable. Of course that could make the log size increase quite rapidly.

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Re: AEMNet CAN

Postby nofalls » Sat Dec 08, 2012 5:58 pm

What do you need Jean? A 2515 and a 2551? Loose DIPs or a development board? PM me an address and I'll send you what you want. I've been burning up digikey for lots of little parts lately.

Mark
Tucson, AZ
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Re: AEMNet CAN

Postby jbelanger » Sat Dec 08, 2012 6:25 pm

Mark,

I do have a 2515 chip. The issue is that I need to make a bench test setup to run some tests and, of course, I need to program the firmware to read the AEM protocol over the 2515. And since I don't have an AEM device, I also need to program some sort of emulator which may or may not be reproducing the AEM output correctly.

I also don't know of anyone who would be ready to test this firmware on the real hardware.

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Re: AEMNet CAN

Postby nofalls » Sat Dec 08, 2012 6:36 pm

Jean,
ah well. I see what you mean. I have no use for it but thought it would be easy to supply some chips if that was what you needed. Back to lurking. ;)

-Mark
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Re: AEMNet CAN

Postby jbelanger » Sat Dec 08, 2012 6:40 pm

Mark,

Thank you for the offer, I appreciate. It was not needed in this case but that could happen in other circumstances.

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Re: AEMNet CAN

Postby inis » Thu Dec 13, 2012 10:44 am

Hi, I'm from MSextra forums. I'm currently looking for a way to get aem canbus to my ms3x. I have a 4 channel uego http://www.jegs.com/InstallationInstruc ... 0-2340.pdf , I currently have all of this set up on a test bench and probably will for a few more months.

I'm willing to help in any fashion that I can.
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Re: AEMNet CAN

Postby jbelanger » Thu Dec 13, 2012 11:00 am

That sounds interesting. I'll have a look at this and see what I can do. It may take a little while before I have something but I'll contact you when I have something that could be tested.

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Re: AEMNet CAN

Postby inis » Thu Dec 13, 2012 11:07 am

sounds good just reply here or pm me, I'll get a email notification. I'm very interested in making this work :D
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Re: AEMNet CAN

Postby chips60bug » Tue Jul 03, 2018 2:41 am

Bringing this one back from the very dead.
The documentation link above has some good info in it about connecting a non-aem device to AEMnet. Maybe you can make heads or tales of what its saying.
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Re: AEMNet CAN

Postby jbelanger » Tue Jul 03, 2018 1:23 pm

Connecting to the AEMnet is not the issue; this is a simple CAN bus so you simply connect CANH on all devices together and the same with CANL. Then you need a terminating connector on each end.

The issue is that the AEMnet protocol uses 29 bit messages at 500k. That is the same as the MegaSquirt CAN protocol which means there is a potential for conflicts. And looking at the document you provided me with all the messages IDs, there are conflicts with CANid 0, 2, 3, 4, 6 (those are ids from the MS protocol). Not all of them are a problem with all AEM devices but CANid 0 is definitely a problem which means the MS3 (or MS2) cannot have the MS protocol enabled when using these. The IOx would be ok if you do not use one those (4 is the default for the TIOx but should be ok because the issue is when using an AEM EMS).

So with the MS CAN protocol disabled on the MS3, you can still transfer data from the IOx to the MS3 using the standard CAN broadcast but you cannot use many of the features and you cannot use any of the MS3 data on the IOx nor can you send command to the IOx over the CAN bus. So you need to configure the IOx through its serial port, log any data from that same port and perform any action only from local ports (such as generic PWM and ON/OFF outputs).

As I mentioned on the msextra forum, the standard CAN broadcast capabilities are limited with the current firmware but they could be used to transfer ADC data to the MS3. Once the new MS3 firmware is available, you will also be able to transfer AFR and EGT data.

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Re: AEMNet CAN

Postby chips60bug » Tue Jul 03, 2018 1:58 pm

jbelanger wrote:Connecting to the AEMnet is not the issue; this is a simple CAN bus so you simply connect CANH on all devices together and the same with CANL. Then you need a terminating connector on each end.

The issue is that the AEMnet protocol uses 29 bit messages at 500k. That is the same as the MegaSquirt CAN protocol which means there is a potential for conflicts. And looking at the document you provided me with all the messages IDs, there are conflicts with CANid 0, 2, 3, 4, 6 (those are ids from the MS protocol). Not all of them are a problem with all AEM devices but CANid 0 is definitely a problem which means the MS3 (or MS2) cannot have the MS protocol enabled when using these. The IOx would be ok if you do not use one those (4 is the default for the TIOx but should be ok because the issue is when using an AEM EMS).

So with the MS CAN protocol disabled on the MS3, you can still transfer data from the IOx to the MS3 using the standard CAN broadcast but you cannot use many of the features and you cannot use any of the MS3 data on the IOx nor can you send command to the IOx over the CAN bus. So you need to configure the IOx through its serial port, log any data from that same port and perform any action only from local ports (such as generic PWM and ON/OFF outputs).

As I mentioned on the msextra forum, the standard CAN broadcast capabilities are limited with the current firmware but they could be used to transfer ADC data to the MS3. Once the new MS3 firmware is available, you will also be able to transfer AFR and EGT data.

Jean

Man, I wish I spoke your language more. My setup is pretty light on the doing things side of the IOx. I think the only output I have is a single high current activating my line-lock, which in turn activates my 3-step on the MS3. I have my LC2 running through a serial connection(won't need this anymore if the 4 ch does its thing). Otherwise I have a whole bunch of ADC inputs being used for egt and other sensors. Will I have issues with the connection? I don't really feel like I'm sending any MS3 data to the IOx at this point. Are you saying that I will have to log all data from the IOx separately? So all of the ADCs i'm currently reading will disappear, unless I pull a separate log from the IOx and overlay that onto my MS3 log? If thats the case, I'll probably avoid the whole AEMnet thing, and just use the 5 ADCs I'll need to send the AFR and Backpressure data from the 4ch into the IOx and then to the MS3. I don't like having to convert, but I'll deal with it if its the only way to make everything play nicely. Or will the new MS3 firmware fix most of those ADC issues and allow me to data log all 3 devices over CAN?
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Re: AEMNet CAN

Postby jbelanger » Tue Jul 03, 2018 3:26 pm

If you're mainly using ADC data on the IOx then you will be able to datalog that on the MS3 if you use the standard CAN broadcasting. Post your IOx and MS3 msq and I'll have a look.

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Re: AEMNet CAN

Postby chips60bug » Wed Jul 04, 2018 1:05 am

That's good news! Heres those .msqs. Let me know if you need something different.
Attachments
2018-07-03_23.02.54.msq
IOx
(31.62 KiB) Downloaded 8 times
2018-07-03_23.02.44.msq
MS3
(276.39 KiB) Downloaded 15 times
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Re: AEMNet CAN

Postby jbelanger » Wed Jul 04, 2018 2:04 pm

You have a couple of strange settings in there. You use CAN ADC17 for one generic sensor but you're not reading it from the IOx in the CAN parameters. And you have enabled two CAN output ports but you're not using them nor have you configured them on the IOx.

Also, you won't be able to use the CAN input for the 3-step input if you disable the MS CAN protocol on the MS3. There is no way to use a digital input with the MS3 standard CAN receiving feature.

Other than that, you could use 4 standard CAN messages to send the 16 ADCs the MS3 currently polls from the IOx. That would use the 16 available CAN receiving values and you would then set those as the CAN ADC local variables which would mean that you wouldn't need to change the other MS3 settings.

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Re: AEMNet CAN

Postby chips60bug » Wed Jul 04, 2018 5:09 pm

The adc17 stuff is for the 5th wideband in the car, I've been using that channel instead of the ego normal way of doing it because i've had the other 4, it was screwing up my tuning to have 5 widebands and 4 cylinders. Sometimes its active, when I'm reading the other 4, and other times, like now, I'm only reading that one, so i think I just have it as my primary. Its unfortunate that I really only seem to mess with this thing about once a year, because I forget why I do half of what I do, and the other half I can't remember how I did it! I'll have to see if there is another way to get the 3 step sorted natively on the ms3.
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