M8 switched output based on speed.

[64hardtop]

Is there a way to configure either a switched or PWM output based on speed with an M8. I have the speed value in the M8 via dig input 3 from the gearbox VSS via a DMC-D. I'm looking to switch a relay to activate the reverse lockout solenoid on the gearbox.

[AdamW]

Yes, you can do this:
You need to use a PWM output, Set it to "aux table" mode. On the parameters screen set X axis to ground speed and Y axis to anything you like(say TP, doesnt really matter), set the output to "switch mode".

When a table is set up in switch mode, any value in the table above 50 will turn the output "on" and any value below 50 will be "off". So say for instance you want to turn on your solenoid above 60Kph you would set all columns above a ground speed of 60 to "100" and set all the columns below 60 to "0".

Like this:

[64hardtop]

Thanks Adam, I've managed to get this far but haven't yet figured out how to map dig IN 3 to represent Ground Speed. On the 'View' 'Main' screen I'm seeing speed data on dig IN 3 but Ground Speed is still reading zero.

[AdamW]

OK, I dont have a M8 to play with so I'm guessing a little but I think the term "ground speed" was mostly part of the traction control function. Looking closer at this function it seems rolling wheel speed must be connected to Dig1, so you will have to shift it from Dig3.
Then you will also have to turn slip measurement on to generate ground speed.

So, under traction control>function, set mode to 0 for slip measurement. Then under traction control>parameters, set slip source to 1 which will tell it that rolling speed is connected to Dig1. That should do it I think.

[64hardtop]

Thanks Adam, all works 'cept it appears the spare PWM output I have is 'toast'. Output on all the time even though the 'View' screen shows it switching. Briefly tried it on the other PWM that is normally used for the ignition (MSD 6) and that works fine. The MSD requires the PWM output for it current capacity otherwise I could use one of the regular outputs. Time for a refurb or upgrade.

[AdamW]

Another option would be to go for a standalone electronic solution: http://www.jaycar.com.au/productView.as ... TID=965#11 something like this could be used to turn your solenoid on or off at a certain speed