I am having trouble getting my MT Prop Tach signal working. It has an active Hall Sensor pickup that returns 6 ppr at 10.25 volts, however its low signal is about 0.45 volts. I got no indication at all in the Sensor Debug screen when I first tried it on a Standard tach input. Because the low signal never actually hit zero volts, I modified the signal with a pull-down resistor and now it produces a 6.25 volt hi and 0.02 volt lo. I switched to a Low Voltage input and still get no indication of anything at the ADC. Looking at the signal with a scope, it appears to be a reasonably good looking square wave. So what's going on here? I looked in the sensor file to see if the tach input had also selected a pullup or pulldown, but the tach inputs are not even in the sensor file. Is the built-in implementation providing a pullup and expecting the tach pickup to provide the ground? Is this then not compatible with the voltage being supplied through the MT harness?
I think one of two things is going on. Either I am still not producing an acceptable signal, possibly due to a conflict of pullups. Or I may have toasted an ADC input during my initial testing. This already happened when I first hooked up the fuel quantity senders (pins 20/21) because my old BMA unit used pullups on their resistive senders and I hit the ADC's with 12 volts. Even after removing these and returning to a purely resistive sender, the two inputs were unresponsive. Moving to a different pair of ADC inputs solved the problem. So perhaps I have toasted my tach input channels too?
Anyone gotten their MT tach signal working yet? Please advise.
I think one of two things is going on. Either I am still not producing an acceptable signal, possibly due to a conflict of pullups. Or I may have toasted an ADC input during my initial testing. This already happened when I first hooked up the fuel quantity senders (pins 20/21) because my old BMA unit used pullups on their resistive senders and I hit the ADC's with 12 volts. Even after removing these and returning to a purely resistive sender, the two inputs were unresponsive. Moving to a different pair of ADC inputs solved the problem. So perhaps I have toasted my tach input channels too?
Anyone gotten their MT tach signal working yet? Please advise.