CDI engine speed signal, function - GF07.16-P-3017IB

ENGINE 647.961 in MODEL 211 

ENGINE 648.960 in MODEL 220 

ENGINE 648.961 in MODEL 211 

Signal assignment 

Fig 1: CDI Engine Speed Signal Function Chart

From the signal from the crankshaft position sensor, the short circuit-proof engine speed signal TNA is generated in the CDI control unit (N3/9) and forwarded to other control units via the CAN data bus.

An alternating voltage is generated by the teeth of clutch plate of the flywheel in the crankshaft position sensor for a turning crankshaft. During this operation, each tooth generates an alternating voltage signal. No voltage is generated as a result of the gap of two missing teeth.

The CDI control unit detects the ignition TDC position of cylinder 1 if, at the point of the second negative signal edge after the gap, the signal "low" (signal voltage 0) is present at the camshaft Hall sensor.

The engine speed signal TNA is a square-wave signal with a constant duty cycle of 6 pulses per engine revolution and a maximum current of approx. 20 mA

If no signal is received from the crankshaft position sensor, the signal from the camshaft Hall sensor is used as a substitute (for emergency mode).