Wanting to build a PCM bench tester??

[delcowizzid]

Most benches don't really need simulated driving for checking code changes but it would be pretty cool .shouldn't be to hard with the atmega and arduino offerings out there to play back a log and have them output the signals

[antus]

What do people want engine simulators for? The use cases I can see are:

1) Developing ADX files... hold everything stable and modify a single input while polling the data stream and watching what has the most significant changes. But, we have done all that, Im not sure there is more need. A regular jimstim can do this.
2) Developing and debugging engine code, such as the enhanced mod or 11p/12p. I know the1 said he has a jimstim in this thread. Typically, twisting a knob to increase eg RPM would be sufficient to test stability or to glitch out of range values.

Perhaps log replay could be used for 2. Are there other use cases?

Whatever hardware such a device is built on will need a lot of analog outputs.

[ar5boosted]

Most benches don't really need simulated driving for checking code changes but it would be pretty cool .shouldn't be to hard with the atmega and arduino offerings out there to play back a log and have them output the signals

It would be fine to include an Arduino, but the point of having 'Tests' is that you are able to have lots of them. I think that the Arduino would struggle in memory size to be a good controller for all the tests that you'd want to have.

The Raspberry-Pi (or a Desktop/Notebook that can run Python and say a Web Server), imho would be better. Because of the fact that it has a bigger file system. We could put a web based control program on that which could select which files you wish to play back. Then we could have a python script to send that file out the serial port [to an Arduino] or attached sensor emulators.

Does anyone have any log files to upload ? so we can investigate this further? or links to these files so that I can browse them online?

What do people want engine simulators for? The use cases I can see are:
..
2) Developing and debugging engine code, such as the enhanced mod or 11p/12p. I know the1 said he has a jimstim in this thread. Typically, twisting a knob to increase eg RPM would be sufficient to test stability or to glitch out of range values.

But I'm sure you'd also want to vary load, not just rpm. Which is really hard to do with two knobs, and much easier to do by sending a calibrated file with the values already set up in a spreadsheet as curves.

I set up a repository on GitHub. If anybody else wishes to collaborate then they are welcome:

- https://github.com/clixx-io/pcmtester

I will probably write some code next week.

[antus]

There are a number of XDL files across the site, can search for XDL to locate them. Its an undocumented binary format, though.

[The1]

Jimstim has one output for crank generator from memory so i use it for 18x + REF signal dont really need 3x for most stuff, i have other circuits that do 3x and cam signal if i need to. 18x will run everything though.

//wheel8
//Holden 18x + REF Signal
11,10,
10,10,
11,10,
10,10,
11,10,
10,10,
01,10,
00,10,
01,10,
00,10,
01,10,
00,10,
0xff // terminating string

[ejukated]

Thanks mate, I'll have to get one on order and test it out

[VL400]

Ive got a number of tools for simulating on the bench, my actual bench tester for simulating an engine is pretty simple. Its progressed since this shot, as it now has a '424 loom piggy backed and another box to simulate a gearbox. Its missing knobs to send vlads OCD over the edge.

Bench And ECM.jpg (276.35 KiB) Viewed 5413 times

You dont need a full 18x3x plus cam for testing a V6 PCM except if you want to trigger via the ign module. Feed directly in to the PCM and both V6 and V8 really only need a square wave input (plus cam if you want to sim seq/banked injection). I've only got a simulator for triggering a factory ignition module or my custom module, it does stacks of factory triggers using an atmega, but the bench above just spits out a square wave via a 556 timer, one for RPM and one for VSS. Has worked well.

PC side I have an ALDL simulator that simulates either a PCM or a vehicle to test how a PCM reacts in a car or ADX development via TunerPro or a Logger.

Having spent hundreds of hours testing code of the years, having an engine playback mode, while neat, is pretty much not required. A static test bench works for 95% of the cases as you are normally wanting to see how code reacts with certain inputs, its only been a couple of times I wished mine had some smarts to it when chasing down a code bug. For the rest of the time a static bench is actually better as you can test the exact response of how values are picked out of tables, or what a single sensor change does to the spark or fuel delivery. Even for ALDL development, static is the way to go as you can change just coolant for example, will see only a couple of bytes change rather than the whole stream.

[delcowizzid]

Do you have a schematic for the square wave trigger circuit

[Gareth]

Its missing knobs to send vlads OCD over the edge.

pisser

[VL400]

Do you have a schematic for the square wave trigger circuit

I cant recall the exact circuit as it was years ago now, but it will be along the lines of this ... http://www.electronicecircuits.com/elec ... -generator

Need to tweak the values though. You want RPM say 0-1KHz (gives 0 - 15,000 RPM on a 8cyl which is enough to crash the PCM) and VSS say 0- 500Hz (around 0-255KPH)

Adjustable voltage is just the normal LM317 adjustable voltage reg with a suitable plug pack feeding it ..