Rockwell Automation 1771-VHSC , D17716.5.74 Very High S - Manual (Page 39)

3–5 Module Programming
Block transfer instructions with the PLC-5/250 processor use one
binary file in a data table section for module location and other
related data. This is the block transfer control file. The block transfer
data file stores data that you want transferred to the module (when
programming a block transfer write) or from the module (when
programming a block transfer read). The address of the block
transfer data files are stored in the block transfer control file.
The industrial terminal will automatically select the control file
based on rack, group, and slot, and whether it is a read or write. A
different block transfer control file is used for the read and write
instructions for your module. A different block transfer control file
is required for every module.
Figure 3.4
PLCĆ5/250 Family Sample Program Structure
EN
BTR
BLOCK XFER READ
RACK:
GROUP:
MODULE:
CONTROL BLOCK
0
0
0
BR000:0
DN
DATA FILE:
BT LENGTH:
CONTINUOUS:
1BTD0:101
0
NO
ER
EN
BTW
BLOCK XFER WRITE
RACK:
GROUP:
MODULE:
CONTROL BLOCK
0
0
0
BW000:0
DN
DATA FILE:
BT LENGTH:
CONTINUOUS:
1BTD0:1
0
NO
ER
BR000:0
EN
BR000:0
EN
BW000:0
EN
1
2
The VHSC module is located in rack 0, module group 0, slot 0. The data obtained by the processor from the VHSC is placed in memory starting
at location 1BTD0:101, and with the default length of 0 is 18 words long. The MSD of counter 0 is stored in 1BTD0:103 and the LSD of counter 0
is stored in 1BTD0:104.
BW000:0
EN
The VHSC module is located in rack 0, module group 0, slot 0. The data sent by the processor to the VHSC is stored in memory starting at location
1BTD0:1, and with the default length of 0 is 64 words long.
VHSC BTR
Enable Bit
VHSC BTW
Enable Bit
VHSC BTR
Control File
VHSC BTR
Enable Bit
VHSC BTW
Enable Bit
VHSC BTW
Control File
BT TIMEOUT 4
BT TIMEOUT: 4
In this chapter, you learned how to program your programmable
controller and you were given sample programs for each family of
controllers. For additional programs, refer to Appendix B.
PLCĆ5/250 Program
Example
Chapter Summary