User Documentation

Communications
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9.3 MEWTOCOL Communication
9.3.1 Overview of MEWTOCOL-COM (RS485)
Command and response functions
The computer sends commands (instructions) to Power Monitor, and receives responses in return. This
enables the computer and Power Monitor to converse with each other, so that various kinds of information
can be obtained and provided.
① Commands
Computer Power Monitor
② Responses
Command and response formats
Command message
(Host computer) Header
Des-
tination
Text
Check
code
Termi-
nator
(To next command)
(Power Monitor) Header Source Text
Check
code
Termi-
nator
Normal response message
• Control codes
Name Character ASCII code Explanation
Header % 25H Indicates the beginning of a message.
Command # 23H Indicates that the data comprises a command message.
Normal
response
$ 24H
Indicates that the data comprises a normal response
message.
Error response ! 21H
Indicates that the data comprises a response message
when an error occurs.
Terminator CR 0DH Indicates the end of a message.
• Destination and source AD (H), (L)
◊ Two-digit decimal 01 to 99 (ASCII codes)
◊ Command messages contain a station number for Power Monitor that receives the message.
◊ When FF (ASCII code table) is used, however, the transmission is a global transmission (sent to all
stations at once).
Note
1) When a global transmission is sent, no response to the command message is returned.