I am working with an LS IS brand servo driver and servo motor. I have some difficulties with getting it to work.

Full manual

I have to mention that I don't have knowledge in servo motors.

I am using a Cypress PSOC (instead of an PLC) to generate 800Hz signal to drive the motor.The main idea is that the motor should turn a whole circle if the driver recieves 800 pulses.

I connected all the power wires(one phase 240V),encoder wires,motor connectors(U,V,W). I also connected the digital control signals. Here you can see typical wiring for Position Operation Mode enter image description here

The servo motor is rotating but not at the speed i wanted(it doesn't complete a full circle in one second,but the 800Hz is provided,I checked it with oscilloscope,and also in the servo menu St-06).It rotates really slow,like it would took couple of minutes to make a full circle. Because the Cypress PSOC provides a square wave signal the servo controller is working in Position Control mode. I have tried to increase the signal frequency but nothing has changed much.

So if anybody can help me I would be thankful.

Servo motor: Servo motor

Servo Driver: Servo driver

Pulse signal: Square wave ST-06 servo driver menu: ST-06

Any numbers like :

  • P0-00
  • P0-26
  • P4-00

represents a menu entry that can be changed

More Information

  1. MODE:Position Control Mode(page 23)
  2. MotorID:731,P0-00(page 98)
  3. Encoder:3,P0-01(page 98)
  4. 100ohm resistor used(page 61),Cypress PSOC gives (0V)-(+5V) signal Resistor

    Parameters:(page 95)

  5. P0-26:1(single)

  6. P4-00:2(page 111),PF+->pin9,PR->pin11 P4-00

Digital Pins:

The following pins are grounded:

  • 10
  • 12
  • 18(emergency stop)
  • 19
  • 20
  • \$\begingroup\$ I have tried to increase the signal frequency ... this does not actually say if you increased the signal frequency \$\endgroup\$
    – jsotola
    Jan 23, 2018 at 20:23
  • \$\begingroup\$ what happens if you decrease the frequency? .... it is possible that the 800Hz is an update clock and it does not control the motor speed. it only controls how often the values are updated. \$\endgroup\$
    – jsotola
    Jan 23, 2018 at 20:25
  • \$\begingroup\$ The speed doesn't changed.I have tried 400Hz,200Hz,100Hz. So I went up with the frequency, up to 600 000Hz(600kHz).It turns every second now. I am guessing ,the position gain parameters need correction. @jsotola \$\endgroup\$
    – iconradez
    Jan 23, 2018 at 20:51
  • \$\begingroup\$ check for a parameter called Electronic Gearing :) . It might need to be set correctly \$\endgroup\$
    – ElectronS
    Jan 23, 2018 at 23:03
  • \$\begingroup\$ Dear @ElectronS ! I consumed articles ,videos,the specific section in the datasheet but still can't get it to work. I get it that the equation is something like: Electronic Gear Ratio = {(TransmissionPerInputPulse * NumberOfPulsesPerRotation)/TransmissionPerMotorRotation)}*deceleration EGR={(TpIP*NoPpR)/TpMR}*deceleration Could you help me how to calculate these? I have a multi turn 19bit encoder incremental. I will be thankful for any kind of information :) \$\endgroup\$
    – iconradez
    Jan 24, 2018 at 17:11

1 Answer 1


I couldn't be more happy. We have solved the problem and now the servo works as it should. An expert helped me who have worked with servo systems. He also highlighted that the Electric Gear Ratio (EGR) needs to be set correctly. The servo has a 19bit encoder so 524288 pulses/rotation.Since the upper controller ,in this case a PIC ,produces 800HZ.

So EGR's numerator had to be set to 524288.(P4-01)

So EGR's denominator had to be set to 800.(P4-05)

(This controller can have 4 preprogrammed EGR relation, i use the P4-01(numerator) P4-05(denominator),i differentiate between this 4 relation with the status of EGEAR2 EGEAR1 input pins' status, i had to set other register values to change the function of the input pins to EGEAR2 EGEAR1)

That's all.

Interesting :I had a test setup here in my home, where the motor was just placed on my workbench , i had set the same parameters for P4-01 and P4-05 but it was not working. At the moment I turned on and i turned the Servo-On signal it moved(jumped a little bit) and the controller displayed an alarm after that the controller has shutted down the motor.It's not happening now.

  • \$\begingroup\$ good work , my hunch was right ( about the electronic gear ratio ) . glad to know that it has worked ... good luck \$\endgroup\$
    – ElectronS
    Feb 11, 2018 at 17:09

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