Cutler-Hammer D320 PLC, User Manual

Page: 97 / 258

Chapter 6: Instructions
85
DIF R
DFN F
Instruction
Mnemonic Edge Contact Range
■
Bit
Word
STR DIF
STR DFN
AND DIF
AND DFN
OR DIF
OR DFN Contact which is On for one scan
at the up or down point of contact
Double words
Ladder
DIF: On at the rising edge ( ) (Off
→
On) for one scan.
DFN: On at the falling edge ( ) (On
→
Off) for one scan.
Description
1. The DIF and DFN instructions may be used more than once in the ladder program for any of
the bit addresses (R, L, M, K, F, and TC).
2. The DIF instruction is a contact which is On for the first scan after the signal has changed
from Off
→
On. The contact is Off for all other scans, when the signal has not changed from
Off or On.
3. The DFN instruction is a contact which is On for the first scan after the signal has changed
from On
→
Off. The contact is Off for all other scans, when the signal has not changed from
Off or On.
4. Both DIF and DFN can be used on the same bit address in a single scan.
Example
Program Expression Time Chart
Contact M002.4 is On if contact R001.4 changes from Off
→
On or contact R001.5 changes from
On
→
Off.
R001.4 M002.4
R (OUT)
R001.5
F
R001.4
R001.5
M002.4
1scan 1scan 1scan