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Communication operation and setting
4
PARAMETERS
4.18.5 Mitsubishi inverter protocol (computer link communication)
(1) Communication
The communication specifications are given below.
(2) Communication procedure
If a data error is detected and a retry must be made, execute retry operation with the user program. The drive unit comes to trip if the number of consecutive
retries exceeds the parameter setting.
On receipt of a data error occurrence, the drive unit returns retry data 3) to the computer again. The drive unit comes to trip if the number of consecutive data
errors reaches or exceeds the parameter setting.
You can perform parameter setting, monitor, etc. from the PU connector of the drive unit using the Mitsubishi inverter
protocol (computer link communication).
Item Description
Related
parameter
Communication protocol
Mitsubishi protocol (computer link) Pr.549
Conforming standard
EIA-485 (RS-485)
Number of connectable devices
1:N (maximum 32 units), setting is 0 to 31 stations Pr.117
Communication
speed
PU connector
Selected among 4800/9600/19200/38400bps Pr.118
Control procedure
Asynchronous
Communication method
Half-duplex
Communication
Character
system
ASCII (7 bits or 8 bits can be selected) Pr.119
Start bit
1 bit
Stop bit length
1 bit or 2 bits can be selected Pr.119
Parity check
Check (with even or odd parity) or no check can be selected Pr.120
Error check
Sum code check
Terminator
CR/LF (presence/absence selectable) Pr.124
Waiting time setting
Selectable between presence and absence Pr.123
Data communication between the computer and
drive unit is made in the following procedure.
1) Request data is sent from the computer to
the drive unit. (The drive unit will not send
data unless requested.)
2) After waiting for the waiting time
3) The drive unit sends reply data to the
computer in response to the computer
request.
4) After waiting for the drive unit data
processing time
5) Answer from the computer in response to
reply data 3) of the drive unit is transmitted.
(Even if 5) is not sent, subsequent
communication is made properly.)
When data is read
When data is written
1) 5)4)
3)2)
∗1
∗2
Computer
(Data flow)
Drive unit
Computer
(Data flow)
Drive unit
Time