User`s manual

18-5
Communication (General Purpose Serial Interface)
18
18-3 Communication format
The communication formats of the commands and responses between the IV-S30 and a personal
computer are outlined below.
*1 Station No.: 00 to 7F(H)
*2 Processing code and text
- They depend on the contents of communication. - See pages 18-1 and 18-7 and after.
- On abnormal termination, no text is provided.
*3 Termination code(H)
The termination code is a 2-digit hexadecimal number.
- When an output is sent through the general purpose serial I/F, 00(H) is sent on normal
termination.
- On abnormal termination, a code other than 00(H) is sent. - See page 20-3.
*4 Checksum code (SCH and SCL)
To improve the reliability of the transmitted data, in addition to a parity check, error detection by a
checksum is used for error detection.
When the IV-S30 does not need to complete a checksum for error detection, use an @ (at sign:
ASCII code 40(H)) in each of the checksum codes SCH and SCL included in the command.
[Error detection using a checksum]
The ASCII code for each data byte, from the processing code to the end of text (prior to the
checksum code), is added. The final value is compared to the checksum code which is treated the
same way. If the two values are identical, the command is considered to be valid. I/F they are not
identical, an error has occurred during transmission.
Header
＊ ＊ ＊ ＊ .............. ＊ ＊
Header
SC
H
CR
SC
L
RC
H
RC
L
Text
Termination
code
Terminator
Processing code
Checksum code
Value increment range
for checksum
SC
H
SC
L
CR
Checksum code
Terminator
Text
Processing
code
＊ ＊ ＊ ＊ ............... ＊ ＊
Value increment range
for checksum
Command
Response
Command
Response
＊ ＊ ＊ ＊ ............... ＊ ＊
Header
SC
H
SC
L
CR
Checksum code
Terminator
Text
Header
SC
L
RC
H
RC
L
Text
*4
*2
Processing
code
*2
Termination
code
*2
*3
Terminator
*2
Processing code
*4
Checksum code
SC
H
CR
Station
No.
*1
Station
No.
Station
No.
:
*1
Station
No.
:
＊ ＊ ＊ ＊ ＊ ＊
...............
Station
No.
:
Station
No.
Station
No.
:
Station
No.