Is this why my speed log doesn't work?

[rogerthebodger]

If the sender is 3 wire you need a supply voltage onto the + and - connectors and the measure the voltage between the - and the 3rd wire colours I don't know

This will need the meter set to the 20 V dc in the white section of the switch

If its a 2 wire sender, you setting will be ok to see where the is on and off as the sender rotates

 

[RogerFoxTerrier]

If the sender is 3 wire you need a supply voltage onto the + and - connectors and the measure the voltage between the - and the 3rd wire colours I don't know

This will need the meter set to the 20 V dc in the white section of the switch

If its a 2 wire sender, you setting will be ok to see where the is on and off as the sender rotates

It's coaxial cable - an inner and braided outer. I don't know if the braided outer carries a signal or is just to stop interference.

 

[RogerFoxTerrier]

A three wire sensor I agree .. but principle is same on the coax version ... the magnet acts on the sensor in the main body and a spike voltage occurs .. as far as I recall - it is NOT an OHMS matter - but a voltage matter ... therefore to test its basically set Multi-Meter to low volts range (0 to 6V) and then connect outer shield to -ve .. centre lead to +ve .. turnm paddlewheel ...

Yes that's the one I saw - but he doesn't show what wires are connected.

 

[awol]

Is this right? If so the actual unit must be dead as it's not giving a reading.


View attachment 183162

Shouldn't there be a probe connected to COM?

 

[RogerFoxTerrier]

Shouldn't there be a probe connected to COM?

I'll try it - checking the voltage of a car battery is about the limit of my multi meter skills!

 

[Daverw]

Shouldn't there be a probe connected to COM?

Yes also needs black in common just as you would if checking your battery

 

[KevinV]

As above, put the black probe (com) to the outer, red to the inner.

Don't hold them in place by hand or you'll be measuring your own skin resistance (and you won't have a hand free to move the paddle wheel)

 

[RogerFoxTerrier]

Right, so with black now in COM and the red probe taped to the inner core and the black taped to the braid, so no fingers involved, I am getting a reading on volts when I spin the wheel. The meter is set to 220m and I get readings typically about 00.1 / 00.2 but sometimes as high as 01.9.

So it's sending a signal - but does that sound right? I guess it also points to a problem with the Duet, which is obviously more to replace!

 

[KevinV]

Right, so with black now in COM and the red probe taped to the inner core and the black taped to the braid, so no fingers involved, I am getting a reading on volts when I spin the wheel. The meter is set to 220m and I get readings typically about 00.1 / 00.2 but sometimes as high as 01.9.

So it's sending a signal - but does that sound right? I guess it also points to a problem with the Duet, which is obviously more to replace!

Rather than spinning it turn the wheel in 90 degree increments, you should get clearer readings

If you want to rule out the head unit I have a spare I could stick in the post to lend