Tachometer setup - M130

[RGAClarke]

What would be the best way to connect and setup an older style UMA tacho in M1 Tune ?
I connected the signal wire to pin A31 (Half bridge output 3) and have tried a 4.7K pull up resistor to 12v without success.
Maybe I am making a hash of the scaling or should be using an output with a positive signal because the tacho worked OK with AUX 1 on the M4 which I am replacing.
Many thanks.
Rupert Clarke

[Ben-S]

Unfourtunatly unless it's been updated I think you need a development license to change the the output to high side. If you don't have a development license and this is the only update you need a solid state relay would probably do the trick.

[RGAClarke]

Thanks Ben.
Could you maybe run me through the scaling. I have seen reference to factors of 1,000 and more on posts relating to other hardware but am not sure how to obtain RPM from the M130. If each engine revolution outputs a pulse I would need to divide the hertz by 60 to obtain RPM which would give a scale of .016667, which of course is not possible.
I have read the context Help Menu over and over but can't see how to work this.
Really appreciate the assistance.
Rupert

[David Ferguson]

The help for the Tachometer Scale, indicates it's the number of pulses per engine revolution. So I would set that to 2 for a 4 cylinder, 3 for a 6 cylinder and 4 for an 8 cylinder to be compatible with the normal coil "Tacho" signal.

[RGAClarke]

Thanks David
That is easy to understand. I was thrown a bit by the scale being referenced in its box as Hz which I assumed meant pulses per second and the Firmware Help menu explanation "the tachometer output frequency is calculated as Tachometer Scale multiplied by by engine speed divided by 360 (with engine speed in degrees/second, or divided through 60 if engine speed is regarded in rpm)."
Anyway greatly appreciate the help.
Rupert

[plohl]

I figured I would ask this here as it pretty much on topic. I just downloaded the M130 GPR package (01.07.0005) and checked to see if I could set up the Tacho to switch battery position, and it doesn't look like I can...

Are we able to switch 12v with the tacho function in the M130 GPA/GPR package and I have just missed it?

If not, will motec ever add this to the standard packages, given it's a 10s fix in build and the M1 has the capability to do it...

Is there a reason as to why this functionality not included?

[chuckk]

Any updates on this ? Running GPR from july 2019 and looks like the high side option isn't possible ? Currently got the tach gauge working with 2k ohms pull-up resistor