Rockwell Automation 1771-IXHR , D17716.5.80 HIGH RESOL.THERMOCOUPLE - Manual (Page 22)

Module Programming
Chapter 4
4Ć4
The PLC–5 program is very similar to the PLC–3 program with the following
exceptions:
You must use enable bits instead of done bits as the conditions on each rung.
A separate control file must be selected for each of the BT instructions. Refer
to Appendix B.
Figure 4.2
PLC-5 Family Sample Program Structure
EN
BTR
BLOCK XFER READ
RACK:
GROUP:
MODULE:
CONTROL:
X
X
X
XXX:XX
DN
DATA FILE:
LENGTH:
CONTINUOUS:
XXX:XX
XX
N
ER
EN
BTW
BLOCK XFER WRITE
RACK:
GROUP:
MODULE:
CONTROL:
X
X
X
XXX:XX
DN
DATA FILE:
LENGTH:
CONTINUOUS:
XXX:XX
XX
N
ER
BTR Enable
Power-up Bit
Pushbutton BTW Enable
1
2
Program Action
Rungs 1 and 2 - At power–up, the program enables a block transfer read
and examines the power–up bit in the BTR file (rung 1). Then, it initiates
one block transfer write to configure the module (rung 2). Thereafter, the
program continuously reads data from the module (rung 1).
A subsequent BTW operation is enabled by a pushbutton switch (rung 2).
Changing processor mode will not initiate a block transfer write unless the first
pass bit is added to the BTW input conditions.
PLC-5 Program Example