PCMTec Development Blog

[rolls]

I'll put serial support for common widebands in my app when I get to it. I'll need some hardware donations though as I only have a TechEdge 2J which uses serial though I imagine they all use a pretty basic format of just spamming a stream of floats.

CANbus whilst it sounds interesting poses a few massive problems, firstly you need a Y cable, secondly the software has to know it exists. As it will be custom you'll have to edit all software to support it, if you are going to do that you might as well just support their serial protocol which would be less work. Most tuning packages can't address other devices, eg they will only poll 0x7E0 eg the PCM, you can't put two devices with the same ID so I doubt you'd get anyone at all to support a canbus wideband. I can't see any good reason to use canbus.

Editing the PCM code would be an absolutely ridiculous amount of work, akin to adding live tuning support. You'd have to write a recompiler for the assembler code to modify all the pointers, would be months of work and nothing would support it.

Using the standard serial interface most widebands support is the way to go and what HPTuners and other companies have done and the approach I'll take. I can't see it taking more than a few hours to implement support for each wideband if you have one on your desk, most of the formats would be the same I imagine. Literally just plug a serial/usb converter in, then add a thread polling a serial port and pumping the floats to your GUI/logging thread that polls canbus via another thread for DMRs etc.

Use the KISS principle everywhere possible.

[Tazzi]

Use the KISS principle everywhere possible.

Literally my favorite saying right there

[Tazzi]

A custom canbus module that gets put into the factory wiring harness would probably the easy(er) approach. The device would have to be smart though.. since if it constantly blasted out onto the canbus.. it would interrupt other modules or even cause problems with tuning. It would need to be enabled/disabled via CAN, timings set to constantly send or set to manual polling which only responds upon request ect.

Again.. possible... but.. worth it?? Maybe not... will always get better resolution by using a separate dedicated cable.

[rolls]

Again.. possible... but.. worth it?? Maybe not... will always get better resolution by using a separate dedicated cable.

A simple serial stream of floats, doesn't get any easier than that. Hell you don't even need to time stamp it as the lag is so low. Could send it via bluetooth or wifi if you were feeling special but unnecessary as whats 1 more cable.

No idea why people still use 0-5v signals, prone to noise and ground offset issues. If you were set on using analog people should use 4-20mA signals like they do in industrial control systems, can run it 50m with all the noise in the world and all you need is a resistor to turn it back in to a 0-5v signal.

Anything else is complexity for no reason.

[MeZmeriZe]

A custom canbus module that gets put into the factory wiring harness would probably the easy(er) approach. The device would have to be smart though.. since if it constantly blasted out onto the canbus.. it would interrupt other modules or even cause problems with tuning. It would need to be enabled/disabled via CAN, timings set to constantly send or set to manual polling which only responds upon request ect.

Again.. possible... but.. worth it?? Maybe not... will always get better resolution by using a separate dedicated cable.

That's what I was talking about.. not one you put into a Y plug on your OBD2.. but rather one that goes straight onto the twisted pair wherever is closes to your wideband (or whatever else you want to hook up.) they come with basic software so you can pre-configure how it identifies itself on the bus etc, then plug it in.. set and forget. Then just pick it up at the other end along with everything else.

Sort of like the usb<->Can adapter next to the VCX in the pic here:

except smarter in that it is basically a serial interface to a pre-settable, CAN host device.

I don't know if it's a worthwhile idea or not, but I like the integration of it. I am fairly certain I already bought one of these.. have to look in my box of stuff and see if I can find it.

I don't know of OBD passthough is a thing (meaning if a laptop was datalogging via CAN via J2534 or whatever to a program like BE or HP tuners etc.. could some other software on the laptop.. say for example a small program that makes a virtual COM port piggyback off the feed and basically turn the new CAN device into a virtual serial device on the laptop that any datalogging software that's serial capable could run with? at the least it means you are not adding much in the way of cabling to the car and you don't have a laptop with serial and or USB devices hanging off every port in your car. Was just a thought.

[MeZmeriZe]

I'll put serial support for common widebands in my app when I get to it. I'll need some hardware donations though as I only have a TechEdge 2J which uses serial though I imagine they all use a pretty basic format of just spamming a stream of floats.

I can help with one of them.. already been though this before.. I have an ASPX D1 wideband with a Bosch LSU4.2 they are just a single byte value. Just divide by 10, and that's your AFR. doesn't get much simpler than that.
http://www.wide-band.com/ very cheap too.

I spent ages figuring out how to wire a serial port to it as back then they didn't offer any help... but eventually got it working and had a program called Winlog working with it. didn't help with BE or any of the others though as none of them had a easy conversion.. like an ini or json file or something you can define your paramaters. (kind of like you can in Torque when you add a new PID and the formula used to get the output value.)

By itself a wideband has little value unless it's mapped to RPM/load/MAF etc etc. but the readout looks good on my pillar anyway and I have it working with BE now via a dataQ and hopefully with whatever Mr Rolls ends up producing.

[Gareth]

Wow, love that wide band mounting, looks very slick

[80gus]

14.6v might be borderline. You could test by disconnecting FEPS on purpose and if it immediately triggers CONDITIONS_NOT_CORRECT

Iv tested from smack bang 12v to 15v.. no dramas with constant supply.

Also have a whirl with varying it between 12v and 15v while reading, seems fine.

Wasnt till the 8v mark where it wasnt too happy.

*Edit
Thats power to ECU and VCM as its all tied together.. so could be either one not being a happy camper at those kinda voltages.

What are you using as a power supply Mr Tazzi?

Im currently using a 2.5A din-rail mounted power supply sits at about 11.8V is adjustable but never found the need, used it for a while now, never been a drama with any ecu type so far. ebay special.

[rolls]

What is that black box, your own multi ecu harness? Looks neat.

Franky that wideband mount looks very cool! I was just using my sct controller on the dash as I never needed it long term though the wideband is still wired in with power to keep it clean.

[80gus]

Yeah it will do e38 ls1 t42 and ford ECUs now I have another for other ECUs