Mitsubishi Electric 800 Series Instruction Manual page 503

 Message format
Programmable controller
• Data check time
Item
Monitoring, operation command,
frequency setting (RAM)
Frequency setting (EEPROM)
Reading/writing parameters
Parameter clear / All parameter clear
Reset command
• Query
A message is sent to the slave (for instance, the inverter) having the address specified by the master.
• Normal Response
After the query from the master is received, the slave executes the request function, and returns the corresponding normal
response to the master.
• Error Response
When an invalid function code, address or data is received by the slave, the error response is returned to the master. This
response is appended with an error code that indicates the reason why the request from the master could not be executed.
This response cannot be returned for errors, detected by the hardware, frame error and CRC check error.
• Broadcast
The master can broadcast messages to all slaves by specifying address 0. All slaves that receive a message from the master
execute the requested function. With this type of communication, slaves do not return a response to the master.
NOTE
• During broadcast communication, functions are executed regarded of the set inverter station number (Pr.331).
502
5. PARAMETERS
5.12 (N) Operation via communication and its settings
Query communication
Programmable controller
(Master)
Inverter (slave)
Broadcast communication
(Master)
Inverter (slave)
Check time
< 20 ms
< 50 ms
< Approximately 50 ms
< 5 s
No reply
Inverter response time
(Refer to the following table for the
data check time)
Query Message
Response Message
Data absence time
(3.5 bytes or more)
Query Message
No Response