LSIS XBE-DC08A, Руководство пользователя, Страница: 1117 / 1284

Chapter 2 Built-in Cnet communication
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B
u
ilt
-in
C
omm
1) User definition communication frame structure
Frame structure of PC Link, communication protocol of Han-Young used in this example, is as follows.
• Frame of temperature controller is executed as ASCII character string, it can read/write defined D, I Register. There
are two protocols, STD standard protocol and SUM protocol adding Check Sum to standard type and protocol is
selected by parameter of temperature controller. Standard protocol is STD”. It starts with first character STX (0x02)
and ends with last character CR(0x0D) LF(0x0A).
The following [Table 2.11.3] and [Table 2.11.4] indicates structure of standard protocol and Sum protocol.
[Table 2.11.3] standard protocol structure
[Table 2.11.4] SUM protocol structure
2) Writing example frame
In this example, present value and setting value is saved in M device area of PLC. [Table 2.11.5] is frame requesting
continuous data and [Table 2.11.6] is frame responding to request.
[Table 2.11.5] request frame
•
DRS : command that request reading continuous D register value. No of data and start address of D register
is necessary.
•
In the example, no. of data is 2 and start address is 01.
[Table 2.11.6] response frame