Rockwell Automation 1747-PT1, D1747NP002 Hand-Held Terminal - Manual (Page 258)

Instructions
Chapter 18
I/O Message and Communication
18–12
Example 2 – Program File 2 of SLC 5/01 Processor at Node 3
Operation Notes, SLC 5/02 and SLC 5/01 Programs
SLC 5/02 processor: N7:0/0 is latched; timer T4:0 is reset; B3/0 is
unlatched (rung 1), then latched (rung 3). SLC 5/01 processor: N7:0/0
is unlatched; timer T4:0 is reset.
Message instruction operation: The message write instruction in the
SLC 5/02 processor is initiated every 1280 ms by clock bit S:4/6. The
done bit of the message write instruction initiates the message read
instruction.
B3/0 latches the message write instruction. B3/0 is unlatched when the
message read instruction done bit is set, provided that the interlock bit
N7:0/0 is reset.
Communication failure: In the SLC 5/02, bit B3/10 becomes set if
interlock bit N7:0/0 remains set (1) for more than 4 seconds. In the SLC
5/01, bit B3/10 becomes set if interlock bit N7:0/0 remains reset (0) for
more than 4 seconds. Your application can detect this event, take
appropriate action, then unlatch bit B3/10.
(U)
N7:0
0
END
0
2
( )
B3
1
(RES)
T4:0
(EN)
(DN)
TON
TIMER ON DELAY
Timer
T4:0
Time Base 0.01
Preset 400
Accum 0
] [
N7:0
0
] [
S:1
15
First Pass Bit
[OSR]
B3
0
] [
T4:0
DN
] [
B3
1
(U)
N7:0
0
(RES)
T4:0
( )
O:1.0
0
] [
N7:0
1
1
3
4
5
6
Bit 0 of the message
word. This is the interlock
bit.
4–second Timer
Latch Instruction – This alarm
notifies the application if the
interlock bit N7:0/0 is not set
after 4 seconds.
O:1/0 energizes cooling
fan.
Bit 1 of the message
word. Used for fan
control.
Message instruction parameters: N7:0 is the message word. It is the
target file address (SLC 5/01 processor) and the local source and
destination addresses (SLC 5/02 processor) in the message
instructions.
N7:0/0 of the message word is the interlock bit; it is written to the SLC
5/01 processor as a 1 (set) and read from the SLC 5/01 processor as a
0 (reset).
N7:0/1 of the message word controls cooling fan operation; it is written
to the SLC 5/01 processor as a 1 (set) if cooling is required or as a 0
(reset) if cooling is not required. It is read from the SLC 5/01 processor
as either 1 or 0.
Word N7:0 should have a value of 1 or 3 during the message write
execution. N7:0 should have a value of 0 or 2 during the message
read execution.
Program initialization: The first pass bit S:1/15 initializes the ladder
programs on Run mode entry.
(L)
B3
10