Automating Manufacturing Systems - Process Control and ...

plc serial - 27.9
To write to other serial ports the message function in Figure 27.7 must be used. In this
example the message block will become active when A goes true. It will use the message
parameters stored in message memory MG9:0. The parameters set indicate that the message
is to Write data stored at N7:50, N7:51 and N7:52. This will write the ASCII string
ABC to the serial port.
A
MSG
Control Block MG9:0
Memory Values:
setup stored
in MG9:0
Data Stored in memory
Read/Write
Data Table
Size
Local/Remote
Remote Station
Link ID
Remote Link type
Local Node Addr.
Processor Type
Dest. Addr.
N7:50
N7:51
N7:52
Write
N7:50
3
Local
N/A
N/A
N/A
20
ASCII
N/A
65
66
67
Figure 27.7
Message Function for Serial Communication
27.2.1.1 - ASCII Functions
ASCII functions allow programs to manipulate strings in the memory of the PLC.
The basic functions are listed in Figure 27.8.