Allen-Bradley 1794-IE4XOE2 Series B, User Manual, Page: 30 / 73

3–4 Module Programming
Publication 17946.5.2 - May 1996
PLC5 Programming
The PLC-5 program is very similar to the PLC-3 program with the
following exceptions:
•
block transfer enable bits are used instead of done bits as the
conditions on each rung.
•
separate block transfer control files are used for the block transfer
instructions.
Figure 3.4
PLC5 Family Sample Program Structure for the 1794IE8
BTR Enable Bit
EN
DN
BTW Enable Bit
1
2
ER
EN
DN
ER
BTR
BLOCK TRANSFER READ
RACK:
GROUP:
MODULE:
DATA FILE:
LENGTH:
CONTINUOUS: N
BTW
BLOCK TRANSFER WRITE
RACK:
GROUP:
MODULE:
LENGTH:
CONTINUOUS:
N
2
1
0
N13:0
9
2
1
0
1
Program Action
CONTROL:
N12:0
DATA FILE:
N13:20
CONTROL:
N12:5
N12:5
15
N12:0
15
Thereafter, the program continuously
performs read block transfers to configure
the module.
Pushbutton
The pushbutton allows the user to
manually request a block transfer write.
N13:8
15
Powerup
Bit
1
At powerup in RUN mode, or when the
processor is switched from PROG to RUN,
the user program enables a block transfer
read. Then it initiates a block transfer write
to configure the module if the powerup bit
is set.
1
Powerup bit included in Series B modules only.
BTR Enable Bit
N12:0
15
BTW Enable Bit
N12:5
15
Figure 3.5
PLC5 Family Sample Program Structure for the 1794OE4
BTR Enable Bit
EN
DN
BTW Enable Bit
1
2
ER
EN
DN
ER
BTR
BLOCK TRANSFER READ
RACK:
GROUP:
MODULE:
DATA FILE:
LENGTH:
CONTINUOUS: N
BTW
BLOCK TRANSFER WRITE
RACK:
GROUP:
MODULE:
LENGTH:
CONTINUOUS:
N
2
2
0
N15:0
1
2
2
0
14
Program Action
CONTROL:
N14:0
DATA FILE:
N15:5
CONTROL:
N14:5
N14:5
15
N14:0
15
Thereafter, the program continuously
performs read block transfers and write block
transfers.
At powerup in RUN mode, or when the
processor is switched from PROG to RUN,
the user program enables a block transfer
read. Then it initiates a block transfer write
to configure the module and send data val
ues.
BTW Enable Bit
N14:5
15
BTR Enable Bit
N14:0
15