IMC CANSAS - Page 323

IGN ignition angle measurement module 323
imc CANSAS Users Manual - Doc. Version 1.9 - 05.12.2014© 2014 imc Meßsysteme GmbH
Ignition pulses per work cycle
This is where to set how many ignitions per work cycle. Available for selection: 2/720 degrees ...
12/720 degrees. These are available for 4-stroke engines in which the work cycle is 720 degrees.
This parameter contributes to the ability of not only the first or just one cylinder's ignition pulses to be
in the signal but ignition pulses from all cylinders. For instance if a 4-cylinder, 4-stroke engine has
ignition at the first cylinder at -10 degrees, and the next ignition at 170 degrees, then KW, then both
had ignition at 10 degrees before TDC. imc CANSAS-IGN uses the specification (in this case 4/720
degrees) in order to convert the 170 degrees to -10 degrees, since it knows from this parameter that
there is ignition every 180 degrees.
Minimum, maximum RPM
The expected RPM range. RPMs determined to be above the maximum RPM are indicated in the
Display with "---". This amounts to overmodulating the input range. The upper limit should therefore
be specified with some reserve capacity. For instance, if the engine rotates at up to 6000 RPM, the
upper limit may not be set to 6000, since a slight fluctuation (6001 RPM) would already exceed the
limit. Instead it would make sense to set the upper limit to 7000. The upper limit may extend up to
20000 RPM. However, it is not advisable to simply set this maximum value, since setting unrealistically
high values increases the risk of capturing disturbance pulses. This is because imc CANSAS-IGN
suppresses pulses which are implausibly high, in response to which the corresponding LED flashes
rapidly. The best value for orientation is the highest rotation speed expected.
If the signal falls below the minimum rotation speed during measurement, the system indicates 0
RPM. Therefore, as the minimum to set, a value well below the idling speed is recommended. The
lower limit prevents creeping rotation from being indicated but ensures that zero is promptly
indicated. The value for the minimum rotation speed's parameter may extend to 100 RPM.
Display update rate
This parameter determines at which rate the device's display's picture is refreshed. Rates between
200ms and 1s are possible. It isn't worth having the display refreshed at a higher rate than the
averaging duration, since the Display is actually showing averaged values. With more strongly
fluctuating signals, a slower refresh rate is recommended in order to make viewing even possible.
Crankshaft sensor
What kind of sensor is connected to the crankshaft in order to obtain information on the crankshaft's
angle?
Sensor with missing teeth: E.g. the engine's own sensor on a cogwheel. The gear pattern must be
specified separately in the parameter "Crankshaft gear pattern".
Sensor with additional zero-pulse (REF): Incremental counter whose number of markings is to be
specified in the parameter "Pulse count per crankshaft revolution". The incremental counter has
an additional zero-output which is to be connected to imc CANSAS-IGN's signal-output "REF".
Counter with one pulse per revolution: only one pulse is returned per revolution of the
crankshaft.