PLC for servo motors (stand alone or with expansion)

Hi team,
We are looking for PLC for servo motors. I’ve reached out over email to the support team (Reference #T4578027 - Servo motor controller [#24810591]), but they referred me to the forum page. Please let me know if you have access to the reference mentioned above or if I need to provide more information. In the nutshell, we are looking for industry standard PLC (programmable logic controller) to control servo motors in a server rack. We are looking for PLC that does not have wifi capabilities or if we can completely turn it off. Please let me know if you need any additional information and looking to hear from you soon. Thank you!

Welcome to the DigiKey TechForum denis.posunko
I see Steve offered a few options from that Technical Reference #.
I do not see a PLC specifically for Servo Motors.
Maybe one of the Engineers on the TechForum can add their recommendation for this.

“Servo motor” is a term that people use to refer to anything from a $5 plastic toy with 3 wires to a $5000 industrial machine with 30. You’ll need to be more specific about the device(s) to be controlled in order to determine the interface requirements.

You’ll also need to be more specific about whether you’re interested in a finished-goods industrial product, or a low-cost item suitable for hobby/development purposes. The finished-goods PLCs listed by DK are generally located here, with extension modules for them found here.

Thank you for getting back to me! I have no problem providing additional information, I just didn’t know what extra info to provide. Yes, we are using a 5V servo motors with 3 wires that cost about $6 each. We are looking for an industry standard PLC that will help us to control those servo motors when required (most likely once in 3 months or so). The more servo motors PLC can control the better. I have never dealt with servo motors and PLC’s before therefore I reached out to see if DK can provide me with a quote for a complete bundle (PLC with expansion) that can control servo motors.

There is another option that we were exploring to use BeagleBone Black Industrial with a compatible controller board (controls 16 servo motors at the time), but from what I’ve been told the PLC is more reliable and considered to be more industry standard product.

take a look at some of the options we have Click Here

Hi Robert, thank you for the link but unfortunately this is not what we are looking for. This page is for servo motors, which we already have. We are looking for PLC to control servo motors. Thank you anyways!

Only you can decide on a solution that’s right for you. Quotes can be provided for specified part numbers and guidance can be offered about the nature of different solutions, but it’s up to you to learn/understand the options and make a selection.

The hobby-type servo drive accessories are typically built around an IC that generates PWM signals in response to commands issued over a serial communications bus, with multiple devices being attachable to the same control interface through an addressing scheme, making control of several hundred hobby servos theoretically possible, and quite easily so. The limited bandwidth of the control signal limits the degree to which motion can be synchronized however, the connectors used are not very robust, and the electrical interface generally lacks protection against static discharge or similar hazards.

At the other extreme, one can consider an industrial PLC with accessories for pulse train communications, of the sort described in this document. Equipment of this sort contemplates industrial motion control applications where precise, tightly-synchronized motion is needed. The connectors are of more robust kind and better suited for industrial installation, the electrical interfaces are protected against ESD and similar hazards, the number of controllable channels is much fewer, and the price tag can be expected to have 2 or more additional digits. I lack familiarity with these product ecosystems and cannot make informed recommendations. If you desire more extensive guidance in this area, you may wish to contact one of our partner automation and integration services providers, listed here.

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Hello Denis,

As I understand your situation, you are looking for a Programmable Logic Controller (PLC) that is capable of driving servo motors such as those you would find in an RC hobby type environment. The RC servos in the sub $10 price range you described typically have a pulse duration interface as described at Servo control - Wikipedia

It is my opinion that you will not find a solution as you are mixing devices from two ends of the spectrum. On one side is the PLC which is an industrial computer with an entry level cost between $400 and $1000. On the other side is an RC servo which is a consumer product designed for a low-cost point.

I’ve been working with electromechanical items for decades. I have never destroyed a PLC but have destroyed a small pile of RC servos. The PLC is a completely different category when compared to the RC servo. You correctly pointed out that the PLC provides a robust solution when compared to microcontrollers such as the BeagleBone or Arduino. We could describe a PLC as “hardened” in that each I/O is protected against electrostatic shock. This is accomplished using technology such as optical isolation and a good measure of protective circuitry to mitigate accidental or technician induced faults.

However, the reliability of a system requires more than hardened hardware. It also requires robust well-designed code. Folks who have never used a PLC will need to learn a new programming language such as ladder diagram or structured text. And, just like programming in C, there are challenges to make the code operate reliably under all conditions.

With that said, I am not aware of any PLC that would interface directly with the RC servo. However, may I present three solutions for your consideration in order of increasing cost:

  1. The BeagleBone or Arduino or multiple networked microcontrollers would be able to drive any number of RC servos. I suspect you could easily find cape / hat to interface with the RC servos. While this is not a typical industrial solution, it may be adequate for your needs.

  2. It is possible for a 24 VDC PLC with PWM capabilities to drive an RC servos provided a resistive voltage diver is used to step the voltage down to 5 VDC. Be very careful with product specifications as not all PLCs will have this drive capability or PWM resolution. Also, there may only be a few I/O pins with PWM capability on any given PLC.

  3. For increased reliability in an industrial environment consider using pneumatics driven by a PLC. While this is the most expensive option, it’s a common and highly reliable solution used in many industrial applications.

Best Wishes,


P.S. This video provides a good introduction to pneumatics under PLC control: PLC Programming Project for Pneumatic Cylinder || PLC programming tutorial for beginners - YouTube. Observe that the pneumatic cylinder features sensors providing feedback the PLC allowing faults to be detected.