Laurel Electronics LAUREATE SERIES COUNTER_TIMER - Manual (Page 35)

The zero index channel contains the same digital filtering that is provided for the A & B channels.
It contains a Polarity jumper that allows selection of either a positive or negative zero index
signal. It also contains two Control inputs, C1 and C2 that control the ANDing of the zero index
signal with the Channel A and Channel B signals. See “Zero Index Setup” below.
The Item indicator light (center right) may be used to determine the location of the Zero Index.
This indicator is lighted while the zero index signal is being received. The zero index signal must
be jumpered for the correct polarity. If, during encoder motion, the indicator is on more than
it is off, it is likely that the zero index signal is jumpered for the wrong polarity.. If so, add a Polarity
jumper to switch E8, position C. If it already has a jumper, remove it.
From the menu, a value may be entered for Offset1. As explained below under “Mechanical
Zero”, Offset1 allows a mechanical zero position different from the zero index position. The
displayed value is the sum of the following:
1. The total bidirectional counts from the optical encoder since the last counter reset or
function reset.
2. The correction factor from the last zero index correction calculation.
3. Offset 1
For example:
Suppose that the encoder contains 30 pulses per revolution and X1 counting is used. Further
suppose that when the mechanics are at 0 position, the zero index is at 10 and the OFFSET
1 = 10 and the counter is reset when the encoder is at the 5 position.
Reset
v
Position 0 5 10 20 30 40 50
Index ^ ^
Internal Total 0 5 15 25 35 45
Correction 0 -5 -5 -5 -5 -5
OFFSET 10 10 10 10 10 10
Display 10 10 20 30 40 50
Internal Total -5 0 5 15 25 35 45
Correction -5 -5 -5 -5 -5 -5 -5
OFFSET 10 10 10 10 10 10 10
Display 0 5 10 20 30 40 50
Once the index point has been passed, the display matches the position. Prior to that, the
display is in error.
When the counter is displaying Quadrature Total and the Total is reset using the Reset & Peak
buttons (Function Reset), the internal Total is set to zero, but the zero index correction is not
affected. This results in a display of the correction value plus Offset 1. To zero the internal Total
and the correction value, the counter must be reset using the Reset & Menu buttons (Meter
Reset). This results in a display of OFFSET 1.
-33-