Laurel Electronics LTM CTR SERIES PULSE, AC or PROCESS TOTALIZER INPUT, SERIAL DATA OUTPUT - Manual (Page 23)

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Phase for Up Count E7
A positive, negative B transition (A leads B)
A positive, positive B transition (B leads A) none
a
Count-by Options E9
X1 = positive edge of A input
X2 = positive & negative edges of A input
X4 = positive & negative edges of A & B inputs none
a
b
Zero Index Polarity E8
Positive
Negative c
none
Zero Index ANDing E10 E8
Zero Index (no ANDing)
Zero Index AND /A
Zero Index AND /B
Zero Index AND A
Zero Index AND B
Zero Index AND /A AND /B
Zero Index AND /A AND B
Zero Index AND A AND /B
Zero Index AND A AND B c
a
a
a
a
b
b
b
b
-
-
a
b
a, b
-
a
b
a, b
OPERATING MODES
• Quadrature Total (Basic or Extended counter) determines position in engineering units by
subtracting counterclockwise transitions from clockwise transitions, as determined by the
signal phase relationship, applying a programmable scale factor to the total, and adding a
programmable offset to the scaled total. The output update rate is set by a Gate Time, which
should be set to its minimum of 10 ms. When the scaled total reaches a programmable
Preset, it is reset to Offset.
A zero index function can zero the counts when a pulse is applied to a zero index (or Z)
channel. Zero indexing uses the programmable Pulses per Rev, which is the number of
pulses between zero index marks times the edges per pulse (1, 2 or 4). Since a wide zero
index pulse could cause a discrepancy in the region between transitions, the zero index
pulse can be shaped by an AND combination with the A or B channels, as set by jumpers.
• Quadrature Rate (Extended counter) determines rate engineering units by subtracting coun-
terclockwise rate from clockwise rate. Both rates can be scaled using Scale and Offset, or
the Coordinates of 2 Points method.
Rate is measured over a gate time, which is
programmable from 10 ms to 199.99 sec. Since one of the two channels may not be
measuring any pulses over the gate time, a Time Out from 10 ms to 199.99 sec is also
programmable. The transmitter update rate will never be less than every Time Out.