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5-2 Command Response Format
For the format of command and response communicated between a host device and controller, there are 1:1 protocol used usually and
1:N protocol used to connect several controllers and the configuration is described below.
The protocol is specified through the dip switch (SW3-4) of the controller.
(1) Command frame
1:1 Protocol
Command code
Data
1:N Protocol
Node No.
Command code
Calculation range of FCS
* In the 1:N protocol, a gray part is added.
Name
SOH
Shows the beginning of the frame with SOH ($01).
Node No.
A number to identify a target controller at the 1:N connection. Specify it through a rotary switch
(SW1/2).
Command code
Specifies the execution (command).
Data
Specifies the parameters (address, number of bytes, etc.) for the command execution or a data to
be written.
FCS
Frame check sequence. This is a code to detect an error in data string. This expresses a calcula-
tion value of horizontal parity of character string between immediately after SOH and immediately
before FCS in two ASCII characters.
Terminator
Shows the end of command with two characters, "*" ($2A) and CR code ($0D).
5-2
Terminator
Data
Terminator
Description
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