Fitting and wiring questions

[Jez]

Hello

Charlie has given me the pin outs for the S6 ECU and I have a few questions.

Attached is a sheet of the pins (remove the .zip - I had to add this to the filename to get the forum to allow me to upload - the file is a .xls Excel spreadsheet) - I've added what I think I should be connecting to each pin. Does this look correct?

My questions:
Do resistive inputs measure resistance to ground? i.e. sensors would have one side to gnd the other to the ECU.

What are THER+ / THER- connections? Are they EGT thermocouple inputs?

Whats the difference between bipolar and unipolar inputs?

Do INJ, IGN and AUX just switch to ground?

Hope I'm not being dumb - just want to clear things up.

Many thanks
Jez

[Jez]

New spreadsheet added - just added EGT and idle control valve on the spreadsheet

[pat]

Jez,

Do resistive inputs measure resistance to ground?

Yes, exactly that. There is a pull-up resistor inside the ECU on these inputs that try to pull the pin up to +5V.

What are THER+ / THER- connections? Are they EGT thermocouple inputs?

Correct again, they are for use with K Type thermocouples, and you just connect your thermocouple directly to the ECU, it has the amplifier built in. From memory on K Types the green is positive (THER+) and white negative (THER-)

Whats the difference between bipolar and unipolar inputs?

Both bipolar and unipolar inputs are capable of simple analogue input but also "digital" / "frequency" type inputs. They have both A/D converters and comparators which allow switching type signals to be monitored.

Bipolar inputs can be used for signals such as those generated by VR sensors. It can be configured as a simple 0 to 5 V input (high impedance), or a -5 to +5 V input, but it cannot be configured as a Thermistor input. The trigger thresholds are definable on bipolar inputs. If a sensor has bipolar output (say a G meter which actually goes negative for negative G) it can be read as an analogue voltage with a bipolar input, the bipolar function is not solely useful for VR type signals.

Unipolar inputs can be used for things like Hall Effect sensors. It can be configured as a simple 0 to 5V input (high impedance), or a Thermistor input (ie pull-up), but it cannot be configured as bipolar. The trigger thresholds are preset and cannot be changed, however should work well with any Hall or Optical sensor.

Do INJ, IGN and AUX just switch to ground?

The INJ outputs are open collector and switch to ground, as do the AUX outputs. The difference between them is that the INJ outputs are capable of handling more current. The IGN outputs are low current push-pull type outputs that slew very quickly on the falling edge. The supply can be either +5V or +12V, and this is selectable by a solder bridge. There is no provision currently for ignition systems that switch on the rising edge, the IGNs are designed to drive the bases / gates of switching transistors as found in most ignitor modules or coils with integral ignitors. This covers most, if not all, production cars, but in the event that an OEM ECU drives coils directly, an ignitor can be fitted, or an S4C / S8C could drive coils directly.

Hope that helps.

Pat.

[pat]

Jez,

I've had a look at your wiring schedule and here are my observations :

The CAS signal on the SR20 if memory serves is picked up by an optical sensor. The lack of a pul-up on the bipolar inputs may be an issue if the optical sensors themselves do not contain the necessary pull-ups or if they're not push-pull type outputs. I would suggest that a safer bet is to stick them on the Unipolar inputs, that way you have the option of turning on a pull-up if you need it.

The ABS signals might be better on the bipolar inputs if they're VR type sensors, but would be OK if they're hall effect.

Everything else looks sensible enough, but it would be wise to make provision for things like the calibration switch (+5V, ANAGND and a 5V input) and enable switches for features such as ALS and launch control (they can be turned on and off as a function of calibration switch position, but why use two positions for the same map with ALS on and off when one position will suffice and ALS can be turned on with a switch). You can also add a traction control switch which allows you to choose the type of control you want (different slip targets etc), so it would be useful to plan for that. Additionally, traction works as a function of either steering wheel angle or lateral G, so you'll want to make provision for one of those too.

It might also be worth your while bringing CAN and RS232 out, if you ever fit a dash like the MXL, MoTeC or Pi then having a telemetry channel already wired will make installation much easier, there's nothing worse than opening up a perfectly good loom to add things! Also consider wiring in things like oil temp, pressure etc, you may not need them now, but if you get a dash like the MXL you can sack most of the gauges, and just set warning alarms on the dash; so long as a parameter is within whatever thresholds you deem appropriate, exactly WHAT it is is largely irrelevant (OK, you might like to keep an eye on oil pressure as an early warning of impending trouble, but you can display it on the dash, so no worries there).

Hope this helps,

Pat.

[Jez]

Nice one Pat - thanks for that.

Did you see my post about the traction control? I presume the TC tables are a 3d table of steering angle (or latteral g) vs speed with configuable amount of slip (they call it spin) - is that right? I can't see where you configure driven / non driven wheels - or is this not required? Does it just cut power if one wheel starts to slip more than the target?

EDIT: Just saw your post on my other thread

[pat]

Jez,

Driven wheel select is in the sensor setup section :

Sensors -> Vehicle Speed -> Driven Wheel Speed Select

It's in sensors because it's a reading, albeit a virtual rather than physical one, and its uses are not necessarily limited to just the traction control strategy.

Regards,

Pat.