Using RPM signal from MoTeC M400 on the DL1

[Patrick123]

Hello guys!

I've got the following problem:
From the auxiliary output of the M400 I can get a "tacho signal" and I connected it to the RPM input of DL1. I started the engine and started logging. The GPS and accelerometer signal was working but in RPM I only had the "standard" 500 RPM signal you also have without any input.

You have any experiences on this item? Do I have to configure anything special in the software? The RPM graph was the 500 RPM line and my engine was doing RPM between 1000 to 8000 RPM.
Hope you can help me
Thanks and best regards,
Patrick

[Turby]

I don't have a problem with my Motec ECU

Try feedin gthe M400 tacho signal into one of the 12V channels on the back of the DL1 and log some data with the engine running. You should be able to see some sort of square wave when you analyse the data.

[Patrick123]

Hey Turby, thanks for your reply!

So you log RPM through a 12 volt analogue input? What signal does the RPM input need that it works with the M400?
What can I do with the square signal, can I watch it directly in the graph as a RPM line or do I have to calculate it first?

Best regards, hope you answer again
Patrick

[Turby]

Hi Patrick

My advice was related to using the data logger itself to view (at low rpm) the rpm signal going from the ECU to the tacho. ie using the DL1 as a 100 Hz digital oscilloscope. At least you can see what the signal is and go from there.
It was not meant to be another way of generating an RPM channel.

HTH
Toby

[RTUSA]

Patrick (or Turby):

What is the signal characteristic supposed to be on that MoTec output?

Turby:

I gather you are using that signal successfully?

Patrick:

If you can get a scope on the MoTec output it would be interesting. Also, for troubleshooting inputs it is often helpful to connect the DL to a PC and use Live Monitor to watch the outputs in real time, its a lot more efficient than run > record > load > graph > fiddle > run....

In any event, you will want to make sure your configuration for the DL1 includes logging RPM - and outputting RPM via serial port if you are going to use Live Monitor.

Hope that helps,

[Turby]

Yep using the std tacho output from the Motec ecu. I believe this signal is simply a 12v square wave.

[RTUSA]

A 12V square wave certainly ought to work unless the duty cycle is extremely short.

Patrick -

Try the Live Monitor and see what that shows.

[Patrick911]

I connected the tacho output to a oscilloscope but it was'nt a 12V signal. Was quite strange, the signal was below 1 Volt so to low to trigger because for the rpm input you need 5 Volts. I wasn't able to use the rpm signal.

But I will try it again on our new Formula Student race car.
Best regards,
Patrick

PS: Patrick123 is the same person as Patrick911 because this poor guy had a system crash and wasn't able to recover login/password.

[Turby]

I find that very strange, it might be worth a call to Motec support, they are very helpful.