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C125 Dash RPM signal from MSD grid

PostPosted: Wed May 08, 2024 7:24 am
by The Outlaw
Hi all new to motec, just purchased a motec c125 dash, currently running an MSD grid ignition and using the c125 mainly as a dash and for logging, trying to work out how to get a tach signal to the dash from the MSD. At the moment there’s a grey tach wire coming from MSD to auto meter tach gauge, could this wire be used to send signal to the dash? If so does anyone’s know how it’s done..
Thanks in advance

Re: C125 Dash RPM signal from MSD grid

PostPosted: Wed May 08, 2024 9:18 am
by SOReilly
You can wire the tach wire to any SPD input of your C125.

It doesn't state how many pulses per rev are generated so you might need to experiment with this a bit.

The SPD pins in hall mode are pulled up to 2.7V, it seems like your MSD box rises to 12v when active so you will probably need to set the hall voltage threshold to 4.680 V, This is in the Spd Levels dialog.

Re: C125 Dash RPM signal from MSD grid

PostPosted: Thu May 09, 2024 2:40 am
by The Outlaw
SOReilly wrote:You can wire the tach wire to any SPD input of your C125.

It doesn't state how many pulses per rev are generated so you might need to experiment with this a bit.

The SPD pins in hall mode are pulled up to 2.7V, it seems like your MSD box rises to 12v when active so you will probably need to set the hall voltage threshold to 4.680 V, This is in the Spd Levels dialog.


Thanks so much for the inf, ill give that a try

Re: C125 Dash RPM signal from MSD grid

PostPosted: Thu May 09, 2024 3:36 pm
by Anthony
Is it not possible to pickup all that info via CAN rather than using up inputs?

Re: C125 Dash RPM signal from MSD grid

PostPosted: Fri May 10, 2024 9:46 am
by SOReilly
Last I remember the grid CAN info is not publically disclosed but yes you probably could