IAI PSEL, Operation Manual

Page: 671 / 1062

3. Program
177
3.6.9 RS232C Communication
[1] String processing commands
Strings are character strings. Strings used by the controllers covered by this manual include
global strings and local strings.
Global strings can be read or written commonly from any program.
Local strings are valid only within each program and cannot be used in other programs.
Global strings and local strings are differentiated by the range to which their number belongs.
Global areas
300 to 999 (700)
Local areas 1 to 299 (299)
The communication with the external devices requires to be conducted with the serial
communication using character lines, thus a use of the string is required.
[2] Explanation of transmission format
Communication performed by the systems covered by this manual is basically exchange of
character strings.
Which character strings should be used for which operations is determined beforehand, so
that the receiving side can recognize each character string and perform the corresponding
operation.
A combination of these strings and characters indicating the end of one character string is
called “transmission format”, and the user can determine a desired transmission format freely.
For example, assume a character string consisting of four characters “HOME” which is used
as a home return command.
It is determined the character to finish the character line should be either “CR” or “LF” on PC.
Therefore, it is necessary to follow this rule.
ఏ㏦ࣇ࢛࣮࣐ࢵࢺ౛
ཎⅬ᚟ᖐᣦ௧
ࢆព࿡ࡍࡿᩥᏐิ ᩥᏐิࡢ⤊ࢃࡾࢆ
♧ࡍᩥᏐ
Example of transmission format
Character string for
home return command
Characters indicating the end
of the character string