[Rusty]

Stop teasing us and give us some pictures of the skins. We are a curious bunch.

I've been trying to figure out a good way to do that. The DashDAQ specifically doesn't do screen dumps (ed: It's running Linux, I wonder if it's running X - it wouldn't have been difficult for them to put a SLIP stack on the host USB interface... then xwd would work... *hmmm*).

To date it's just been a 6x4 grid of tiny boxes full of data, which wouldn't photograph well. Now it's got nifty dials and things, and I'm thinking about how to get video over the shoulder that includes it and the dash.

 

[Jeff N]

I did ask about the second OBD-II connector in the car, and they muttered about how it's proprietary and may not even be OBD-II signaling/voltages - and how that might damage the DashDaq if I tried to plug it in... I'm somehow dubious of that, but I don't think I'm keen on risking that expensive a unit just to try it out.

Does the maintenance manual have anything to say about signalling and what data's available on the passenger side OBD port?

According to the Volt service manual (page 12-248, Volume 3), the standard driver-side OBD-II connector provides access to a primary CAN bus that contains the emissions-related data required to be provided by all new cars. It also provides access to two additional data links - another GM-specific "chassis" CAN bus used for other various data without congesting the primary CAN bus and a GM-specific low speed CAN bus for sending less time-critical data.

The passenger-side connector provides access to a "high voltage energy management" CAN bus and also a separate "powertrain" CAN bus.

So, the driver and passenger side use the same physical connection standard but are wired differently and provide access to different data busses. The connector pins are assigned somewhat compatibly in that power is on pin 16 and scan tool ground is on pin 4. The energy management CAN is wired to pins 3 and 11 which are not used on the driver-side connector (but may be used on non-GM OBD-II connectors). The powertrain CAN bus uses pins 12 and 13 in a way that is electrically compatible with the chassis CAN bus on the same pins on driver-side connector.

 

[Rusty]

AThe passenger-side connector provides access to a "high voltage energy management" CAN bus and also a separate "powertrain" CAN bus.

Does the manual describe a pin-out for the passenger side connector? Where do the two CAN busses there lie?

Drew Tech (the DashDAQ folk) won't hook up to anything not sanctioned by the manufacturer. But I'm sure the $30 sCANner might be interested...

 

[Jeff N]

Does the manual describe a pin-out for the passenger side connector? Where do the two CAN busses there lie?

Yes. There is text description that I was quoting earlier and there is also a later pinout diagram for both the driver and passenger connectors. All the CAN busses I described earlier use the same electrical signaling and network standards as the primary CAN bus. It helps to look at the Wikipedia standard OBD-II pinout table together with my earlier writeup. I think that pins 3 and 12 are the "high" pins of the 2 CAN busses on the passenger side and pins 11 and 13 are the "low" pins. I'll double check later tonight when I have access to the manual.

http://en.wikipedia.org/wiki/On-board_diagnostics#OBD-II_Diagnostic_connector

 

[WopOnTour]

I put complete pin outs to both DLCs in the other scan tool thread a while back
http://gm-volt.com/forum/showthread.php?5328-Volt-Diagnostic-Tool&p=90997#post90997
I've lso just added the schematics for the Primary GMLAN, Chasiss Expansion (X84 DLC under LH IP)
and the 2 HS GMLAN busses on X84B (Aux DLC under RH IP)
HTH
WOT

PS> I've had some expereince with Drew Techologies hardware in the past, and it's top-notch stuff (much of it used in GM Engineering)
So to have a tool like this being offered into the consumer channel, at this price point, is excellent!

 

[Jeff N]

I put complete pin outs to both DLCs in the other scan tool thread a while back
http://gm-volt.com/forum/showthread.php?5328-Volt-Diagnostic-Tool&p=90997#post90997
I've lso just added the schematics for the Primary GMLAN, Chasiss Expansion (X84 DLC under LH IP)
and the 2 HS GMLAN busses on X84B (Aux DLC under RH IP)

Cool. I had forgotten about the other thread.

 

[Rusty]

The attached video shows some of the capabilities of the DashDAQ used with the Volt. In this video the Volt accelerates from an on-ramp onto the freeway, drives a bit, then takes an off-ramp off the freeway. The DashDAQ screen layout has 4 dials, with a total of 20 analog gauges being shown on them. This is done by having up to 8 different needles in each dial.

Yellow Needle: Motor B
Green Needle: Motor A
Purple Needle: Chassis (axle RPMs, axle Torque, and battery kWatts)
Blue Needle: ICE (Not demonstrated in this video)
Brakes are Yellow: Requested Torque, Blue: Regen Torque (also not demonstrated)
The Bar at the bottom is the amount of mechanical braking applied (Request-Regen)
1x needles are solid. 10x needles are dashed. Only torque and kWatts have 10x needles.

The analog gauges are:

[FONT=Courier New]
Upper Left: RPMs (-2K to +10K)                   Upper Right: kWatts (-10/100 to +20/200)
Lower Left: Torque Ft-Lbs (-20/200 to +40/400)   Lower Right: Brakes Ft-Lbs (0 to 1000)[/FONT]

The digital gauges are color coded to match the appropriate needle.

Note the behavior of Motor A during non-modest acceleration, and while leaving the freeway. It's clear the 70 MPH reference given by GM is only a really REALLY broad guideline! Also note that this in no way represents anywhere near an efficient demonstration of Volt driving!

 

[pauldon]

Thanks, this is really good stuff. I was sold before but now I must have one. There are too many questions about whats going on 'under the hood' that I must answer. I'll get one ordered early next week and call them to purchase the Volt specific parameters. Thanks for the motivation!

 

[Rusty]

Thanks, this is really good stuff. I was sold before but now I must have one.

You might want to hold your horses *just* a little bit. I've got a MAJOR beef with them about their unit, how they advertise it, and how it performs.

Specifically, the Volt "Extension" isn't an extension at all. You can either have all the generic OBD scanning codes, plus the GM extensions or you can have the Volt "extensions". Loading up the Volt driver excludes any other J1962 drivers (which includes ALL the other OBD drivers they seem to have).

So if you're interested in Volt-special type stuff, you can't see any of the things you'd normally expect to see with any other car. If you operate 100% EV, that's not too much of a problem. But if the ICE turns on, about the only things you can see are RPMs, Torque, and coolant temps. Specifically, there's no way to estimate instantaneous MPGs, as the MAF isn't available and there's absolutely no way to estimate it.

And that's a biggie for me.

So while this is neat stuff, I in absolutely no way can recommend the DashDAQ at this time.

It doesn't help that I identified this problem as critical when I first bought it nearly a month ago, they agreed it was a problem and said they'd work with me to find a resolution. Since then? *crickets*

If I don't hear something soon I'll likely be contesting the charge on the credit card for false advertising, and sending the unit back.

[later edit:] I'll also note that when I complained to Drew Tech (the makers of DashDAQ) that the unit panicked with 24 dials on the screen, they said the most gauges that could be put on the screen is 24 (since that's the most any of the provided skins uses). This video shows 20 analog gauges on the screen, plus 11 digital gauges, 4 buttons, and a text box. The skin editor tool doesn't like this much more than the unit itself does, and support there seems pretty shaky as well. None of their demo skins uses overlaid analog gauges. This displays up to 8 analog gauges overlaid onto a single dial. I honestly don't know what they're going to think about that, either.

 

[pauldon]

And even though I know the specs on the motors, actually seeing it eclipse 111KW which would exceed 300A of current from the HV battery reminds me again of the incredible amount of instantaneous power that battery has to deliver. It's also a good reminder of why you have the keep the green globe centered to get the range you want. That is a TON of power being consumed right there.

 

[pauldon]

Specifically, the Volt "Extension" isn't an extension at all. You can either have all the generic OBD scanning codes, plus the GM extensions or you can have the Volt "extensions". Loading up the Volt driver excludes any other J1962 drivers (which includes ALL the other OBD drivers they seem to have).

Wow. This is exceedingly lame. Did they offer any explanation of why it works that way? I would assume the other $95 extensions don't work this way as that would be more broken than the Volt scenario it would seem.

 

[Rusty]

This is exceedingly lame. Did they offer any explanation of why it works that way?

Nope. I specifically asked, and also asked if the Volt extension relies on the second CAN bus contained on the driver's side OBD connector (which would at least be a plausible reason)

*crickets*

 

[Rusty]

And even though I know the specs on the motors, actually seeing it eclipse 111KW which would exceed 300A of current from the HV battery reminds me again of the incredible amount of instantaneous power that battery has to deliver.

The DashDAQ isn't actually getting measurements on power. It's querying for amps and volts (it has separate queries for the battery and each motor). So I'm using the rescale calculator to calculate watts, which is more interesting to me. When I ask it to create logs I ask it to also store away the individual measurements, but I don't actually know what the voltages or amps were in this particular recording.

But yes, the battery can supply quite a bit of instantaneous power. And quite effortlessly, which is one of the things that makes a Volt suck a kick to drive! :- )

 

[JetJock]

Rusty,

How did you set it up to do that? I didn't know you could overlay the different gauges.

 

[Rusty]

How did you set it up to do that? I didn't know you could overlay the different gauges.

I don't believe Drew Technologies knew you could overlay gauges either :- ) While not difficult, it wasn't trivial. And I'm only using the skin editor to do compile, I'm directly editing the XML files myself by hand. For an example of the poor user interface, if you want to change the gauge ranges or what signal's on the gauge, it can't be done from the touch panel UI. It can only reliably be done by editing the XML file and recompiling it (digital gauges excluded, those can be done from the UI).

I sent them an e-mail a couple days ago with a link to the YouTube video, along with asking them the status of the generic OBD/Volt OBD exclusion. I haven't heard anything back yet.

As to your base question, the trick is that each gauge has a bitmap (although I'd call it a pixmap, from my X11 days) for the gauge background. There's nothing that says the bitmap file size has to have anything to do with the gauge size (it can be 1x1), and their color definitions are 32 bit aRGB, where 'a' is an alpha channel allowing transparency (my dashed needles are dashed color/transparent, though it's rather difficult to see - I couldn't figure out how to get PhotoShop lite to do that either, so I hand edited the bitmap files with a binary tolerant text editor).

So I just define a bunch of gauges with the same origin and shape (with different needle bitmaps), and the background bitmaps thus don't draw over the preceding gauges at that (x,y) point.

 

[ChrisC]

Oh. My. God. I just died and went to heaven. The cloud where you get to overdose on primo data over and over.

Now, to scrape together $600 for this ... Hmmm. I wonder if I can find someone else in Atlanta who would be willing to split this with me. Or maybe some of my track racing buddies already have one ...

I'll be adding this to the FAQ, for sure!

Two stupid questions:

1. If I buy one of these things, it would theoretically be useful to me in any car, right? Putting aside the Volt exclusion issue Rusty has raised.

2. If someone here develops a layout that I like, can I take that layout (the XML file that Rusty mentioned?) and install it into mine?

 

[Rusty]

1. If I buy one of these things, it would theoretically be useful to me in any car, right? Putting aside the Volt exclusion issue Rusty has raised.

Most any car. All modern cars with an engine in the USA are required to support a minimum generic set of OBD PIDs (which is to say, the DashDAQ gets absolutely *nothing* from a Leaf - I tried it). DrewTech claims enhanced support for a variety of makes and models. Additional extended PIDs are available for the large US manufacturers, and Subaru. They also have licenses for some aftermarket devices as well.

2. If someone here develops a layout that I like, can I take that layout (the XML file that Rusty mentioned?) and install it into mine?

Pretty much. The easiest transfer is a ".ddskin" file, which is the compiled XML "look and feel" file (aka "skin"). The other XML file is the config file, which selects which input signals go to which gauge in the skin. If you want to modify the skin file you'll need to download their skin editor (which I'm only using to compile the skin file into the ddskin file - "editor" is something of a misnomer) and you'll need the base skin xml.

So it's not difficult.

 

[WopOnTour]

Nope. I specifically asked, and also asked if the Volt extension relies on the second CAN bus contained on the driver's side OBD connector (which would at least be a plausible reason)

*crickets*

Rusty, as I said before I commend you for breaking trail with the DashDaq. Although I had questioned some of the "non-existant" PIDs over in the other thread, it's actually very cool that you can creat custom PIDs by combining parameter values with your own custom formulas and combine them in different display configurations. Very sweet features.

The 2nd aux DLC (RH) really isnt a consideration here. The various networks are all technically "gatewayed" to the the primary DLC (LH) by specific modules that are present on more than one bus. So EVERYTHING should be available to the LH side DLC. In service the only real use of the RH DLC is for service programming of specific modules.

Great work.
WOT

 

[Rusty]

The 2nd aux DLC (RH) really isnt a consideration here. The various networks are all technically "gatewayed" to the the primary DLC (LH) by specific modules that are present on more than one bus.

I did get something of an answer to that yesterday. Apparently things get confusing if they try to talk to more than one ECU at a time. The Generic and GM Extended PIDs are all on one ECU. The Volt Extensions are on a different ECU. They say if they get some engineering time on it, they may try seeing what happens if they relax the restriction.

So we'll see...

And it was JetJock who broke trail. I just followed along behind, with a machete :- )

 

[tboult]

Have a question for those with the DashDaq and/or ODBC.
In this thread
http://gm-volt.com/forum/showthread.php?9695-Cold-weather-is-another-reason-for-a-HOLD-button/page2
it was
posted that if you pop the hood while on, which starts the ICE, then close it and drive, the ICE keeps running.

Can someone check if, as one starts driving, it starts charging or is in CS mode, or is it using EV to drive and the ICE is just buring fuel. (I.e. is the a poor man's hold mode or just a ICE based heater?)