Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 466)

Appendix E
Application Example Programs
E–23
File 7, Rung 3
Converts the BCD thumbwheel value from BCD to integer. This is done
because the controller operates upon integer values. This rung also
”debounces” the thumbwheel to ensure that the conversion only occurs on
valid BCD values. Note that invalid BCD values can occur while the
operator is changing the BCD thumbwheel. This is due to input filter
propagation delay differences between the 4 input circuits that provide
the BCD input value.
FUN GRAPHIC PARAMETER
CODE SYMBOL MNEMONIC NAME ADDRESS VALUE FORCES
–––– ––––––– –––––––– –––– ––––––– ––––– ––––––
10 MPS
23 –]/[– ANI 1’st pass bit
S1/15 0
51 –EQU– AND–EQU previous scan’s BCD input value
SRCA N13 0000H
SRCB N14 0000H
101 FRD debounced BCD value
SRC N14 0000H
DEST N12 0000H
22 –] [– AND
Math Overflow Bit
S0/1 0
42 –(U)– RST
Math Error Bit
S5/0 0
12 MPP
106 MOV this scan’s BCD input value
SRC N14 0000H
DEST N13 0000H
File 7, Rung 4
Ensures that the operator cannot select a paper thickness of 0. If this
were allowed, the drill bit life calculation could be defeated resulting
in poor quality holes due to a dull drill bit. Therefore, the minimum
paper thickness used to calculate drill bit wear is 1/4 in.
FUN GRAPHIC PARAMETER
CODE SYMBOL MNEMONIC NAME ADDRESS VALUE FORCES
–––– ––––––– –––––––– –––– ––––––– ––––– ––––––
50 |–EQU– LD–EQU debounced BCD value
SRCA N12 0000H
SRCB 0
106 MOV debounced BCD value
SRC 1
DEST N12 0000H