The system adopts the EM760 series frequency converter closed-loop control method, one frequency converter is used as the main machine, 

and the other three are used as slave machines, which drive the four circular mechanical wheels of the rolling mill to rotate synchronously. 

The raw material round steel is rolled synchronously by four wheels. It is made of square steel with a square cross section.

The master sets the speed through the analog quantity of the external potentiometer. In order to meet the requirement of four-wheel synchronization, 

the speed of the slave is given by the master through RS485 communication, and the 485 communication transmits the output frequency 

of the master to the slave as a given frequency. Due to the inevitable mechanical error, the steel will be slightly bent after forming. In order to solve this problem, 

the output frequency of the slave machine is introduced into the auxiliary frequency for fine-tuning. The fine-tuning range is 0~1.5HZ, 

so the output frequency of the slave machine = the main frequency Source A + auxiliary frequency source B or the output frequency of the slave = main frequency source A - auxiliary frequency source B. 

The start and stop of the master and slave are controlled by external terminals.

Inverter main power circuit wiring diagram:

Inverter control board terminal wiring diagram：

Terminal wiring diagram of the control board of the main engine inverter:

Terminal wiring diagram of the control board of the auxiliary machine inverter:

Remarks: If the auxiliary machine does not need fine-tuning of speed, it is not necessary to connect the auxiliary speed given potentiometer.

Parameter setting of the host inverter

The given frequency of the host inverter is given by the potentiometer through the analog port AI1, and the start and stop are controlled by the external terminals. 

The specific parameters are as follows:

F00.01=2;The control mode is set to closed-loop control mode

F00.02=1;The start and stop mode is set to external terminal control

F00.03=1;Select terminal control mode as 1

F00.04=1;Select the given frequency analog channel as AI1

F00.23=4;Set the carrier frequency to 4 to reduce motor noise

F01.01=22;Set motor power

F01.02=380;Set motor rated voltage

F01.03=42.8;Set motor rated current

F10.05=1;Select the communication function to be valid

F10.06=1;Set the inverter as master

F10.07=0;Set the data to be transmitted as the inverter output frequency

Output frequency of auxiliary machine = main frequency source A±auxiliary frequency source B, 

the value of main frequency source A is given by 485 communication, 

the value of auxiliary frequency source B is given by AI1 analog channel, the specific parameters are as follows:

F00.01=2;Select the closed-loop control method

F00.02=1;Select the external terminal mode to control the start and stop of the inverter

F00.04=7;Select main frequency source A frequency is given by communication

F00.05=1;Select the frequency of auxiliary frequency source B given by the analog channel of AI1

F00.06=2;Select the given frequency of the inverter as the main and auxiliary calculation result

The value of F00.08 is set according to the site conditions, if you want the output frequency of the auxiliary machine to be fine-tuned, set it to 1. 

Set it to 0 if you want to increase the fine-tuning of the output frequency of the auxiliary machine

F00.23=4;Set the carrier frequency to 4 to reduce motor noise

F01.01=22;Set motor power

F01.02=380;Set motor rated voltage

F01.03=42.8;Set motor rated current

F02.01=1;Set X2 terminal as running function

F02.33=0.5;Set the bias of the analog input to 0.5V

F02.36=3;Set the maximum range of analog input to 1.5HZ

F10.05=1;Select the communication function to be valid

F10.06=0;Set the drive as a slave

1. The stable speed accuracy of EM760 series inverter under FVC control mode is as high as ±0.02%, which ensures that the speed of the four mechanical wheels is basically the same.

2. The EM760 series inverter supports the internal networking of the inverter, and the slave machine completely follows the output frequency of the master to run. 

Compared with the analog value setting, this scheme completely avoids the speed deviation caused by the analog value error.

3. The standard machine supports LCD keyboard, which is convenient for operation and debugging. You can understand the meaning of each function parameter by referring to the text description of the keyboard.