MSEL Master Relay to Motec M150

Hi all

I have a track-only Subaru BRZ with a push button start, with a Motec M150 ECU, Motec C125 Dash and a MSEL Solid State Master Relay (link). I am novice learning to wire, and would appreciate your help.

I am seeking some guidance on the best approach to wiring the PDM / ECU output from the Master Relay to the M150 to kill the engine. The PDM / ECU output from the Master Relay is in its default configuration, which is active high, half bridge (so Output 'on' is V battery and Output 'off' is GND).

The stock push button start is wired to the M150 via UDIG9, which is configured as Driver Switch 1. Driver Switch 1 is used to control Engine > Run in the M150.

Is there a way to wire the PDM / ECU output as a separate input to the M150 and logically combine that input with the input from the stock push button start (such that both must be on for Engine > Run to be "On" and if either input is off Engine > Run is "Off")?

In the meantime, I have installed a 4 pin normally open relay to the input wire from the push button to UDIG9, such that the PDM / ECU output switches the relay. A diagram is below. This works fine, but seems like a bit of a hack job given all the smarts of the Motec M150.

Any help would be greatly appreciated.

Regards

Michael

Is the pushbutton start active low? If so, I would use that relay as the Ignition Power relay, and have the MSEL be the high-side of the trigger, and the push-button be the low side. That way both the MSEL (high) and the push button (low) have to be true for the Ignition Power to be enabled. Either one off will disable the ignition and thus stop the engine.