Rockwell Automation 1794-ID2 U.MNL INCREMENTAL ENCODER User Manual
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Overview of the Incremental Encoder Module
Publication 1794ĆUM015B-EN-P - May 2001
Value 0
Counter Register
Counter Register
Preset Register
Logic
RangeLimited = 1
RangeLimited = 1
Logic
Count Up pulse (+)
Count Down pulse (-)
Counter = 0
Counter = PresetValue
Note: Ifthe preset register value = 0, the counter retains the value 0.
Filter Function
The filter function is only valid during mode 000 (pulse counting).
You enable the filter function by setting bits in Control word 2. Each
counter can be individually filtered by enabling its associated filter
control bit. However the filter is common to both counters.
When a counter is in mode 000 and its filter is enabled, signal A is
internally sampled at a rate 8 times higher than the filter constant. A
change of state in A has to be valid during 4 samples before it
reaches the counter.
Output from Filter
Sample Clock
Internal Counter
Aj
1 2
3
0
1 2
0
1 2
0
3
3