B–7
B–7
RLL Communications Programs
Data Communications Module, 2nd Edition, 2/03
Identifying the slave station memory area to read or write
The Read Network (RX) or Write Network
(WX) is the last instruction in the routine. Use
the RX if you want to read data from the slave,
or use the WX instruction if you want to write
data to the slave.
You have to specify the data type and the
starting address for the slave. (Remember,
you have to specify a data type that will work
correctly with the number of bytes specified.)
If you use the RX instruction, the data will be
read from the slave starting at the address
specified. If you use the WX instruction, the
data will be written to the slave starting at the
address specified.
Data Type
and
Address
Example:
Read from slave starting at Y0.
LDA
O40600
LD
K3
LD
K201
RX
Y0
NOTE:
If you are exchanging data with a DL305 system, it is important to understand how to
reference the DL305 memory locations. For example, the DL305 I/O points are accessed with
the V data type or the GY data type, even though the DL305 does not actually have those data
types present in the CPU. The table on the next page provides a detailed cross reference.
Master PLC
Slave Address 1
Slave Address 2
Y20 - Y37
15
8
0
Y0 - Y17
Slot 0
CPU
Slot 1
Slot 2
Slot 3
Slot 4
Содержание D2-DCM
Страница 4: ...D2 DCM Data Communications Module Manual Number D2 DCM M...
Страница 37: ...1A Cable Diagrams...
Страница 47: ...Data Communications Module 2nd Edition 2 03 B RLL Communications Programs...
Страница 58: ...Data Communications Module 2nd Edition 2 03 C Using the D2 DCM with MODBUS...
Страница 67: ...Data Communications Module 2nd Edition 2 03 D Using the D2 DCM with Modems...