IMC CANSAS - Page 313

IGN ignition angle measurement module 313
imc CANSAS Users Manual - Doc. Version 1.9 - 05.12.2014© 2014 imc Meßsysteme GmbH
It is also possible to use an incremental counter having an
additional zero output, which is connected to the imc
CANSAS-IGN as the reference signal (REF). The zero
output then indicates the crankshaft's zero marker.
Incremental counter with zero output
For monitoring selected cylinders, a camshaft
sensor must be connected.
This sensor returns one impulse per revolution
of the camshaft.
Camshaft sensor
Precision
imc CANSAS-IGN captures when the signals cross defined thresholds, at a resolution of fractions of
microseconds. From these data it is possible to calculate the ignition angle with precision of 0.1
crankshaft degree and better, even at high RPMs. Thus, if there even is any imprecision, then it is in
determining the pulse times. This is mostly because the pulses are not steep enough and a threshold
value must be determined. then the threshold selection influences the time when the pulse is detected.
Also, the sensor equipment is subject to transit times which vary with the RPMs and cannot be corrected.
The sensor equipment itself has some imprecision. For instance, cogwheels may not be manufactured
exactly, VRS sensors return RPM-dependent phase shifts. Some of the effects can be compensated by
appropriate parameterization of imc CANSAS-IGN, but some can't.