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Danfoss FC51 “Modbus RTU” via Modbus Poll Software

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Hello friends!
In previous articles, showed you how to use various devices to control Danfoss FC51 inverter through Modbus RTU. Today will guide you in the simplest way to control Danfoss FC51.

Today will use Modbus Poll software (extremely light software and simple to install) to control Danfoss FC51 in the fastest way. With this complete control and monitoring of the inverter, we can quickly control the inverter without having to connect many wires.

Computer & Danfoss 51 “Connection Diagram”

Note: A 120Ω terminal resistor should be used if the communication distance between PC and VFD is long distance.

Danfoss 51 Modbus RTU Configuration

To be able to control Danfoss FC51 inverter with Modbus RTU we need to set the following parameters

Registers for Control

>>> VFD Control Address = 49999 (hex)

+ Set Registers 49999 = 1148 (dec) >>> Forward Run
= 33916 (dec) >>> Reverse Run
= 1084 (dec) >>> Stop
= 1212 (dec) >>> VFD Reset

>>> VFD Frequency Reference = 50009 (hex)

+ Reference Setting = 0 to 16384(dec) ~ (0 to 100%)

Registers for Data Monitoring

+ Voltage Output Address = 16119 (dec)

+ Frequency Output Address = 16129 (dec)

+ Current Output Address = 16139 (dec)

Danfoss FC51 Modbus Programming

+ Setting Frequency Command

+ VFD Control Command

+ Read Voltage Output

+ Read Frequency Output

+ Read Current Output

Detailed Instruction Video


Related Software and Documents

+ Modbus Poll Software Free Download

+ Danfoss FC51 Manual PDF Download (Password Extract:

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