National Instruments Direct Injector Driver System Manual
© 2013 National Instruments. All rights reserved.
Pattern Type
EPT Type
Selections
Pattern Description
N - M
EPT N-M 7
N-M patterns have N evenly spaced teeth and M
missing adjacent teeth (gap) on the crankshaft trigger
wheel. M is limited to 1 or 2 missing teeth. N is stated
in terms of evenly spaced teeth, as if there were no
missing teeth. For example, a 60-2 pattern would
consist of 58 physical teeth followed by two missing
teeth. EPT N-M function can be configured to track
360 or 720 degrees depending upon an optional
camshaft input. When tracking 360 degrees for
2-stroke engines, the camshaft input is ignored.
When tracking 720 degrees for 4-stroke engines,
the camshaft input signal must be TRUE during
every other crank tooth gap. The cam signal can be
manipulated using the offset and extend functions to
satisfy this requirement.
N + 1
EPT N+1 9
N+1 patterns have N evenly spaced teeth and a
single additional tooth (Plus1), placed between
two evenly spaced teeth, on the crankshaft trigger
wheel. The Plus1 tooth can be located at one of two
different positions between two evenly spaced teeth,
advanced or retarded. N is stated in terms of evenly
spaced teeth, as if there were no additional teeth. For
example, a 6+1 pattern would consist of 6 physical
evenly spaced teeth and an additional physical tooth
placed between two evenly spaced teeth. EPT N
+1 function can be configured to track 360 or 720
degrees depending upon an optional camshaft input.
When tracking 360 degrees for 2-stroke engines, the
camshaft input is ignored. When tracking 720 degrees
for 4-stroke engines, the camshaft input signal must
be TRUE during every other Plus1 tooth. The cam
signal can be manipulated using the offset and extend
functions to satisfy this requirement.
Encoder
EPT Enc 2
EPT Enc 4
Encoder patterns have N evenly spaced teeth on the
crankshaft with a separately sensed single reference
(index) tooth on the crankshaft or camshaft. The
rising edge of the reference must occur between
the same two crankshaft teeth rising edges each
engine cycle. The EPT Encoder function can be
configured to track 360 or 720 degrees. When
tracking 360 degrees, the reference tooth is located
on the crankshaft, yet is directed to the CamSig input
of the EPT function. When tracking 720 degrees, the
reference tooth is located either on the crankshaft or
on the camshaft. When located on the crankshaft,
then an additional cam phase signal must be present
) every other crank
reference, such that every other crank reference is
allowed to pass through to the CamSig input of the