21
The B channel may be set as Up, Down or Direction. In the direction mode, the B channel is no
longer a count source, but controls the count direction of the A channel input. This state control
works as an ‘exclusive-or’ with the channel A direction. Thus, if B input is in the ‘Down’ state and
A channel is set to Down, pulses at the A input will increment count.
Table 7. Count Behavior with B Channel Set as Direction Control
When A channel has been set to either Quadrature or Reverse Quadrature settings, the B
channel internally behaves as a direction control.
2)
To set the B channel:
a)
In the Input Setup area, after entering the A Chan value, the display will flash
between
b chan
and the counter’s default (
dir
).
b)
When the display shows
dir
, press
.
c)
Use the arrow keys to change the value, then press to accept the selection
and proceed to the next menu category, Count Setup.
NOTE:
The B channel will not show in the menu when Quadrature or Reverse Quadra-
ture has been selected for the A Channel input.
4.3
Scaling and Decimal Point Position
(Count Setup)
Prescale
The S660 counter allows for prescaling of display values. Prescaling allows the counter to
display a more accurate number than its 6-digit capacity might otherwise allow by making the
positive count the most significant digit.
Generally speaking, the smaller the scale value, the more accurate the count will be. The S660
has four prescale values, 1.0 (default), 0.1, 0.01, and 0.001.
An example of this application is as follows:
A 600 pulse-per-revolution encoder is used to measure cable before it is cut to the proper length.
There is a wheel (one foot in circumference) attached to the encoder, in direct contact with the
cable. The user wants to see the counter display feet to 1/100' accuracy (to two decimal points).
With the default prescale of 1.0, one rotation of the wheel would be displayed on the counter as
00.0016'. (1/600, where 1 is the number of feet as shown by wheel rotation and 600 is the
number of pulses per revolution.) However, by using a prescale of 0.01, the resolution has been
multiplied by 100, allowing the counter to display 0.16667, increasing the accuracy of the
ENTER
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