510 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 13 Special Instructions (FBC, DDT, DTR, PID)
Example: When enabled, the DTR instruction masks value_1. If there is a difference in
the two values, the rung-condition-out is set to true.
A 0 in the mask leaves the bit unchanged.
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The rung remains false as long as the input
value does not change.
The rung remains true for one scan when a
change is detected.
0
183 1 87
Mask = 0FFF
187
Source
Reference
183
183
183
Current Scan
Previous Scan Previous Scan
Current Scan
Example 1 Example 2
9
7
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1