Rockwell Automation 1760-xxxx Pico GFX-70 Controllers User Manual - Manual (Page 195)

Publication 1760-UM002B-EN-P - March 2005
Wiring with Pico GFX-70 4-85
High-Speed Incremental Encoder Counters
Pico GFX-70 provides two high-speed incremental encoder counters CI01 and
CI02. The high-speed counter inputs are hardwired to the digital inputs I1, I2,
I3 and I4. These counter relays allow you to count events independently of the
cycle time. You can enter upper and lower threshold values as comparison
values. The contacts will switch according to the actual value. You can use a
CI.. counter if you wish to define a start value.
The CI.. counters operate independently of the cycle time.
Counter Frequency and Pulse Shape
The maximum counter frequency is 3 kHz.
The signals must be square waves. The mark-to-space ratio is 1:1. The signals
on channels A and B must lead or lag by 90°. Otherwise the counting direction
cannot be determined.
Wiring of a Counter
The following assignment of the digital inputs apply:
• I1 counter input for the counter CI01 channel A
• I2 counter input for the counter CI01 channel B
• I3 counter input for the counter CI02 channel A
• I4 counter input for the counter CI02 channel B
IMPORTANT
Double the number of pulses are counted as a result of the
internal method of operation of the incremental encoder.
The incremental encoder evaluates the rising and falling
edges. This ensures that the pulse count is not affected by
oscillation of a signal edge. If the number of pulses are
required, divide the value by two.