Controlling a servo motor with ML1200

I had planned to use PTO instructions to control a servo motor, single axis only. We have a ML1200 BWA model. According to the ML1200 manual, "The PTO instruction should only be used with ML1200 BXB units. Relay outputs are not capable of performing very high speed operations."


What other options do I have to control the servo? I am new to servo controls, so maybe there is something obvious I am missing. Thank you.

What brand and model servo are you trying to control? What are you trying to accomplish? Servos can be configured to accept several different types of command signals.

Steve Bailey said:

What brand and model servo are you trying to control? What are you trying to accomplish? Servos can be configured to accept several different types of command signals.

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It's a SureServo from AD. This would be a simple Peck Cycle on a drill press. I was actually just re-reading your response to an earlier thread I had. You suggested using Sequencing functions to control. This may be what I was missing...

I did my first Servo project using the Sureservo's from AD. I considered using PTO
but ended up using Mod-bus off com 0 with messaging and it was very easy. Not sure what series 1200 you are using since the series A & B only have 1 com port and would be a pain in development. I used the ML 1400 Which was nice since I had channel 0 set for my mod bus and used the Ethernet through a switch for both programming and VFD controls.
There is a nice demo RS500 program from Archie posted on this site which I used to understand the Mod bus protocol and that coupled with the Sureservo Manual I was able to control several Servos in my application

Since I am fairly new to PLCs, I was not aware of the MODBUS protocol. My original plan was to program the servo drive using the software from Automation Direct (program the position setpoints that I am looking for), and then use PLC outputs to connect to the Servo Drive Inputs. The LL program would trigger the outputs as needed in sequence.

If I understand correctly, I can use a MODBUS connection between the servo drive and PLC which would bypass the need to program the servo drive separately. This option would entail incorporating the servo drive settings into the LL program. Is that correct? Are there any other advantages to using MODBUS (besides just having one program to deal with)?

Send me a PM with your email address and I'll send you a sample project file that used a Sure Servo to control the vertical position of a grinding wheel on a surface grinder. Operator could jog the axis down until the wheel just kissed the workpiece, then capture the position and enter the amount to be ground off and the number of steps, similar to what you want to do. The project includes a DL06, Sure Servo, and a C-More EA7. The PLC communicates with the Sure Servo via Modbus.

Steve Bailey said:

Send me a PM with your email address and I'll send you a sample project file that used a Sure Servo to control the vertical position of a grinding wheel on a surface grinder. Operator could jog the axis down until the wheel just kissed the workpiece, then capture the position and enter the amount to be ground off and the number of steps, similar to what you want to do. The project includes a DL06, Sure Servo, and a C-More EA7. The PLC communicates with the Sure Servo via Modbus.

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Thanks Steve I will do that.

Sounds like Modbus communication is the way to go between the drive and PLC. Next I will need to see how to set up the ML1200 for that since there is only 1 comm port.

Can the ML1200 be set up as a MODBUS master? Seems I am finding some conflicting info on that. I have a series C controller, FRN 6. I believe it will need set up as a Master, and the Sure Servo drive as the Modbus slave.