Modbus Rtu Communication Specification - Mitsubishi Electric FR-A800 Series Instruction Manual

*1 The signal within parentheses ( ) is the initial status. The description changes depending on the setting of Pr.190 to Pr.196 (Output terminal
function selection).
*2 No function is assigned in the initial status for the separated converter type.
 Multi command (HF0)
• Sending data format from computer to inverter
Format
1 2
Inverter
A2 ENQ station
number
• Reply data format from inverter to computer (No data error detected)
Format
1 2
Inverter
C1 STX station
number
*1 Specify the data type of sending data (from computer to inverter).
*2 Specify the data type of reply data (from inverter to computer).
*3 Combination of data 1 and data 2 for sending
Data type
Operation command
0
(extended)
Operation command
1
(extended)
*4 Combination of data 1 and data 2 for reply
Data type
Inverter status monitor
0
(extended)
Inverter status monitor
1
(extended)
*5 The error code for sending data 1 is set in error code 1, and the error code for sending data 2 is set in error code 2. Mode error (HA), instruction
code error (HB), data range error (HC) or no error (HF) is replied. (Refer to

5.15.6 MODBUS RTU communication specification

Operation by MODBUS RTU communication or parameter setting is possible by using the MODBUS RTU communication
protocol through the RS-485 terminals of the inverter.
686
5. PARAMETERS
5.15 (N) Communication operation parameters
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3 4 5 6
Send
Instruction Time
data
code (HF0) delay
type
3 4 5 6
Send Receive Error
data data code
*1 *2 *5
type type 1
Data 1 Data 2
Set frequency (RAM)
Set frequency (RAM,
EEPROM)
Data 1 Data 2
Output frequency
(speed)
Special monitor
search engine
Number of characters
7 8 9 10 11
Receive
data *3
Data 1
*1 *2
type
Number of characters
7 8 9 10 11
Error
code
*4
Data 1
*5
2
Run command (extended) is same as instruction code HF9. (Refer
to page 685.)
Inverter status monitor (extended) is same as instruction code H79.
(Refer to page 685.)
Replies the monitor item specified in instruction code HF3 for special
monitor. (Refer to
page 776
12 13 14 15 16
*3
Data 2
12 13 14 15 16
*4
ETX
Data 2
Remarks
Remarks
page 446.)
for details on the error codes.)
17 18 19
CR/
Sum check
LF
17 18 19
CR/
Sum check
LF