In previous posts, plc247.com has written instructions for you to use the Mitsubishi QJ71C24N Module to connect and control different temperature controllers, today I will guide you to control the FR-E700 Series inverters as well over Modbus-RTU Communication Protocol.
Mitsubishi inverter FR-E700 Series (or D700 Series) has built-in RS485 Comm. Port. so we can easily connect to Module QJ71C24N.
Mitsubishi QJ71C24N & FR-E720 “Wiring Diagram”
Below is the Modbus-RTU RS485 communication diagram between the QJ71C24N Module and the Mitsubishi FR-E720 Inverter.
Mitsubishi FR-E720 Modbus Parameters Setting
We need to set the following communication parameters so that the FR-E700 Series inverter can be controlled and monitored using Modbus-RTU protocol:
- Pr117 = 1 (Slave Address)
- Pr118 = 3 (Baudrate 9600)
- Pr119 = 0 (8bit, stop bit = 1)
- Pr120 = 2 (Even)
- Pr121 = 9999
- Pr122 = 9999
- Pr123 = 9999
- Pr124 = 1
- Pr340 = 1
- Pr549 = 1
- Pr79 = 2 (Last Setting)
Mitsubishi FR-E720 Modbus Registers Address
Note: Control Address = Starting register address (decimal) – 40001
>>> vfd Control Address = 40009 – 40001 = 8 (dec) = 8 (hexa)
- Set Word 8(hexa) = 0000 0000 0000 0010 = 2 >>> Forward Run
- Set Word 8(hexa) = 0000 0000 0000 0100 = 4 >>> Reverse Run
- Set Word 8(hexa) = 0000 0000 0000 0000 = 0 >>> Stop
>>> Frequency Setting Address = 40014 – 40001 = 13 (dec) = D (hex)
>>> Output Frequency Address = 40201 – 40001 = 200 (dec) = C8 (hex)
Module QJ71C24N “Modbus RTU” Configuration
Please configure the QJ71C24N Module according to the following steps:
+ Step 1: Create Project folow your PLC
+ Step 2: I/O Assignment
+ Step 3: Channel.2 (RS422/485 Port.) Parameters Setting
+ Step 4: Sent Parameters to PLC
+ Step 5: Disable “Echoback”
- Echoback references to the function in which data transmitted by RS-485 (2-wire) is returned about the local station’s “RDA and RDB”.
- Echoback references to the function in which data transmitted by RS-485 (2 wires) is returned about the local station’s “RDA and RDB”.
>>> Set G450 = 1 (Disable Echoback) / = 0 (Enable Echoback)
QJ71C24N & FR-E720 VFD “Modbus Registers Configuration”
+ Go to Tool “Serial Communication Module…”
+ Protocol Configuration
Registers Address Config.
>>> Protocol No.1: Func = 06 / Write Single Registers
- Slave Address = D100
- Register Adress = D101
- Register Value = D110
- “Error Code” = D300
>>> Protocol No.2: Func = 03 / Read Holding Registers
- Slave Address = D200
- Starting Address = D201
- Quantity of Registers = D202
- Registers Value Response = D210 “From D210…D335 depending on the number of Registers (D202) to read”
- “Error Code” = D300
Important: Need to set “Receive Wait Time”, if Set = 0, then when Modbus Command gives error, Module will wait for infinity time and need to Reset PLC
+ Disable “Echoback” & Error Reset
+ Communication Distribution
+ Frequency Setting Command
+ VFD Control Command
+ Data Response Monitoring
+ HMI Address Mapping
Detailed Instruction Video
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