Unitronics VFD Quick Start Guide
Guy Sela
Oct-9th, 2018 9:05

Unitronics VFD Quick Start Guide

Motor Wiring

There are 2 wiring options; the wiring is determined by the grid voltage. The motor voltage should be ≤ Grid voltage (See Image 2).

Star: Connect the starting or finishing ends of three coils together to form the neutral point. A common wire, Neutral is taken out from the neutral point. 

Delta: Delta winding allows third-harmonic currents to circulate within the transformer, and prevents third-harmonic currents from flowing in the supply line. Delta connected windings are not commonly used for higher transmission voltages (138 kV & above).

Important wiring guidelines:

  • Use shielded twisted pairs cable for the RS-485 communication.
  • Connect the UniStream SG (signal ground) terminal or Vision and SAMBA pins 2 or 5 (0V (0V reference) to the COM terminal on the VFD.
  • Connect the communication cable shield to the GROUND (EARTH) terminal on the UniStream RS-485 terminal block, for Vision or SAMBA connect the shield to the PLC ground (FG pin) on the power terminal (connect the shield on one side only, don't connect the other side to avoid ground loops).
  • Make sure that the last communication loop VFD 120OHM termination is on (right DIP switch or jumper is UP) and for all the other VFD's are off (right DIP switch or jumper is DOWN), as additional check measure the resistance between the 485+ and 485- terminals on the PLC and make sure that the value is 60OHM.
  • Ground the UniStream PLC with shortest possible way.
  • Separate the VFD and PLC ground points.
  • Connect the RS485 shield to the earth point.
  • In order to reduce noise disturbance, we highly recommend to use 19,200 bps baudrate on the RS-485 network. 

VFD Configuration

The following image shows you how to use the VFD Keypad.

Configure the Motor Parameters:

P02.01 – Rated power of asynchronous motor [KW].

P02.02 – Rated frequency of asynchronous motor

P02.03 – Rated speed of asynchronous motor [RPM]

P02.04 – Rated voltage of asynchronous motor [V] P02.05 – Rated current of asynchronous motor [A]

                        Image 2

Get the Motor Moving

Set the Run command channel source

The VFD offers 3 ways to select the RUN command:

·         Keypad- set P00.01 to 0.

·         Terminal- set P00.01 to 1 MODBUS- set P00.01 to 2

Frequency Source Command

Frequency is set via P00.06.

Change the frequency via:

1.   Keypad- set P00.06 to 0 Keypad Arrows.

2.   Terminal*- set P00.06 to 1 potentiometer wheel from keypad.

3.   MODBUS- set P00.06 to 8 via RS485. Note - Frequency can be also controlled via Analog , high speed input etc...

Auto Tuning

Motor parameter autotuning is required when using sensorless vector mode. (P00.00 = 0 or 1)

Autotuning is set via P00.15

0: No operation.

1: Rotating autotuning Comprehensive motor parameter autotune. It is recommended to use rotating autotuning when high control accuracy is needed.

2: Static autotuning 1 (autotune totally) It is suitable in the cases when the motor cannot de-couple from the load. The autotuning for the motor parameter will impact the control accuracy.

3: Static autotuning 2 (autotune part parameters); when the current motor is motor 1, autotune P02.06, P02.07, P02.08

Communication Parameters via MODBUS:

Modify these parameters according to your requirements:

1.   Set P14.00 (local communication address) to the inverter ID number (1 -247)

2.   P14.01 (communication baud ratio)  

3.   P14.02 (Digital bit checkout).

Note - Default settings: ID=1, Baud rate=19200, Digital bit checkout =Even, 8, 1

The same baud rate and digital bit should be configured in the VFD Properties in UniLogic/VisiLgoic.


In case you wish to send commands to the VFD via the terminal (IO) connect the PLC digital outputs to the VFD digital inputs (S1-4).

Note- the connection can be wired as Source or Sink (default).

Use a U-shaped contact tag to set NPN or PNP mode, and the internal or external power supply. The default setting is NPN internal mode.

                           Image 3 * 

Image3 example for UMI-B1 UL Series.

Example settings:

·         Forward - P05.01 (S1 terminals selection) to 1.

·         Reverse - P05.02 (S2 terminals selection) to 2.

·         Forward jogging - P05.03 (S3 terminals selection) to 4.

·         Reverse jogging - P05.04 (S4 terminals selection) to 5. 

Note - The terminal selection can be modified. For more options, please see VFD User manual.

Reset the VFD to factory defaults

To restore factory defaults, write the value 1 to P00.18.

Please note that:

1.   The motor parameters in group will not reset. 

2.   The communication parameters will reset only after power up.

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