July 2013 10.10 Data Transfer by PLC 1917
10.10.2 PLC modules
With the following PLC modules you can control the data interfaces from the
PLC:
Modules 9100 and 9101: Assign/release the data interfaces
Module 9102: Interrogate the status of the interface
Modules 9103 and 9104: Transmit and receive a string from the string
memory. The transmit and receive buffers for the PLC are 128 characters
long. Since every STRING ends with an END character, a STRING can only
be up to 127 characters long.
Modules 9105 and 9106: Transfer a block of binary values (bytes) from the
word memory
Module 9107: Read bytes from the receiving buffer without erasing the
buffer
STRINGS and binary data are transferred using ASCII characters.
Example: Transferring a binary block
When transferring binary data starting from the address B126, the ASCII
characters <F> <A> <8> <1> etc. are transmitted in sequence from the word
memory through the interface. Each byte contains two ASCII characters. The
transmitting and receiving buffers each hold 63 bytes.
Address Value ASCII character
...
B126 11111010 $FA
. 10000001 $81
..
..
..
To Next Page
Loading...
