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Mitsubishi QJ71C24N “Modbus RTU” Siemens V20 Tutorial

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Hello friends!
Continuing the series of articles using the Q-Series PLC in combination with the QJ71C24N Communication Module to control different devices through the Modbus-RTU protocol, today will continue to guide you to control the “Siemens Sinamics V20” inverter.

In this article, I will guide you and make the sample program in the simplest and easiest way possible.

QJ71C24N & Sinamics V20 “Connection Diagram”

Siemens Sinamics V20 inverter has a built-in RS485 communication port, so we can connect to it simply and easily.

Siemens Sinamics V20 “Modbus RTU” Configuration

In addition to the basic parameters of the inverter installed according to the motor (frequency, current, voltage…) we need to install the following communication parameters so that the Sinamics V20 inverter can control and monitoring using the Mdobus RTU protocol.

Siemens Sinamics V20 Registers Adress

+ VFD Control Address = 99 (dec)

  • Set Word 40100 = 1151 >>> Forward Run
    = 3199 >>> Reverse Run
    = 1150 >>> Stop
    = 1278 >>> VFD Reset

+ VFD Frequency Reference Address = 100 (dec)
(Speed Reference = “0 to 100%” = “0 to 16384 dec”)

  • Frequency Output Address = 23 (dec)
  • Speed Output Address = 24 (dec)
  • Current Output Address = 25 (dec)

QJ71C24N “Modbus RTU” Parameters Setting

To configure the Mitsubishi QJ71C24N Module we do the following:

+ Step 1: Create New Project folow your PLC

+ Step 2: I/O Configuration

+ Step 3: Channel.2 (RS485) Parameters Setting

+ Step 4: Write parameters to Module QJ71C24N

+ Step 5: Disable “Echoback”

Echoback refers 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 & Siemens V20 “Modbus Configuration”

+ Go to Serial Communication Module Tool

+ Protocol Add/Read/Write

In this project I configure as follows (you should configure like me if you are new to this Module)

1. Protocol No.1

>>> Func = 06 (Write Single Registers)

+ Slave Address = “D100”

+ Register Adress = “D101”

+ Register Value = “D110”

+ “Comm. Error” = “D300”

2. 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)

+ “Comm. Error” = “D300”

Note: Need to set “Receive Wait Time” (if Set = 0, error communication will be Infinite Wait) you can configure it like this:

PLC Programming Example

+ System Ready & Error Clear

+ Communication Distribution

+ Frequency Setting Command

+ VFD Control Command

+ Read Data Monitoring

Project Video Tutorial

+ Download GX-Works 2 Mitsubishi PLC Software
+ PLC Mitsubishi Q03UDV & Weintek HMI “Connection Tutorial”
+ Download Siemens Sinamics V20 Manual PDF

Password Extract:

If in the process of using the Mitsubishi QJ71C24N to control the Siemens V20 inverter, you need any support, please comment below the article, will reply to you as soon as I read the comments.

Best Regards!

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