Mitsubishi Electronics FR-D740-012 ユーザーズマニュアル

The communication specifications are given below.

∗1

If a data error is detected and a retry must be made, execute retry operation with the user program. The inverter comes to trip if the number of consecutive
retries exceeds the parameter setting.

∗2

On receipt of a data error occurrence, the inverter returns reply data 3) to the computer again. The inverter comes to trip if the number of consecutive data
errors reaches or exceeds the parameter setting.

You can perform parameter setting, monitoring, etc. from the PU connector of the inverter using the Mitsubishi inverter
protocol (computer link communication).

Mitsubishi protocol (computer link) 

Pr. 549

EIA-485 (RS-485)

—

1:N (maximum 32 units), setting is 0 to 31 stations

Pr. 117

Selected from among 4800/9600/19200 and 38400bps

Pr. 118

Asynchronous

—

Half-duplex

—

ASCII (7 bits or 8 bits can be selected)

Pr. 119

1bit

—

1 bit or 2 bits can be selected

Pr. 119

Check (even, odd) or no check can be selected

Pr. 120

Sum code check

—

CR/LF (presence/absence selectable)

Pr. 124

Selectable between presence and absence

Pr. 123

Data communication between the computer and
inverter is made in the following procedure.

1) Request data is sent from the computer to 

the inverter. (The inverter will not send data 
unless requested.)

2) After waiting for the waiting time
3) The inverter sends reply data to the computer 

in response to the computer request.

4) After waiting for the inverter data processing 

time

5) Answer from the computer in response to 

reply data 3) of the inverter 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)

Inverter

Computer

(Data flow)

Inverter

Time