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Modbus RTU + STM24 & SWM24 Integrated Steppers

by Matt Cole

Whether you are new to our products or a long-time Applied Motion Products user, we think you may be interested in what we have been working on recently. Why? Because these products and features can make your life easier by shortening the time to complete your motion control project while reducing complexity, cost, and component count.

Perhaps you saw our feature article last month regarding our newly supported communication protocol, Modbus RTU: Dial “M” for Modbus!. Maybe you have heard about our NEMA 24 integrated steppers (STM24 and SWM24), which combine the advanced features of our microstepping drive and controller into a single device with a NEMA 23 motor mount.

In case you missed it, Modbus RTU is Applied Motion Products’ newest fieldbus protocol, which is now available on the following integrated stepper products:

Modbus RTU operates on a serial link, and is optimized for use on RS-485. It operates on the principle of registers, which can be used to monitor the drive’s behavior, send data to and from the drive, and execute commands. It is uniquely suited to PLC applications since PLCs use a similar memory model by design. As such the Modbus RTU protocol is typically already integrated into most PLC and HMI platforms as a generic driver. For more information on Applied Motion’s implementation of Modbus RTU, click here.

Take a look at our Application Notes for Modbus RTU that are available for download from our website. The engineers at Applied Motion Products have already done the hard work for you by preparing and documenting these easy-to-use examples:

Detailed instructions for setting up the STM24 integrated stepper are contained within these compressed files as well as example project files for a growing selection of compatible PLCs and HMIs. Check out a complete list of our downloadable app notes here.

The STM24 drive+motor offers savings on space, wiring and cost over conventional motor and drive solutions. The STM24 complements Applied Motion’s popular STM17 and STM23 drive+motor family, delivering higher torque output with more options for connectivity.

The “Q” models feature stand-alone programmable operation using the Q programming language. This versatile language includes high-level features such as complex motion, multi-tasking, conditional programming, math functions, and register access. Stored Q programs can be started and stopped over Modbus, providing distributed control where the drive performs complex tasks on its own, reducing network traffic. “S” models accept step and direction, analog input, joystick control, and streaming host commands using the SCL language. Both S and Q models with RS-232 or RS-485 communication offer four optically isolated “flex I/O” points which can be individually configured for digital input or output. A 12-bit analog input is also included. The STM24 provides up to 340 oz-in of torque and can be powered from 12 to 70VDC. All STM models are CE certified and ROHS compliant.

The STM24 is also available with an Ethernet interface, allowing Q and SCL commands to be streamed at speeds up to 100 MBits/sec over standard Ethernet hardware. Interfacing to a Rockwell PLC? An EtherNet/IP option is also available.

An optional encoder (4000 counts/turn), integrated into the motor housing, provides stall detection and/or stall prevention. Applied Motion’s proprietary stall prevention algorithm monitors rotor lag and automatically reduces speed or acceleration to avoid motor stalls, allowing 100% torque utilization.

The SWM24 integrated stepper is designed for wet and dusty operating environments while delivering expected reliability, performance and value. Applied Motion Products has responded to the need for products that can withstand more demanding environmental conditions by developing this integrated drive+motor that has been certified IP65 capable. Featuring oil shaft seals, engineered gaskets and special coating technology, our IP65 offerings have been engineered for the toughest environments with in-house testing well beyond the expectations of the standard. The entire integrated package is engineered to resist the ingress of water and dust to IP65 standards. All connectors are sealed, M12 style. Mating cord sets are available from stock to get you up and running quickly. All SWM24 models provide 340 ounce inches of holding torque and are available with all the same features as the STM24 family.

  • Matching DC power supplies for both the STM24 and the SWM24 models are also available. Excellent performance will be achieved when powered by our PS320A48 48 volt DC power supply.
  • To learn more about our IP65 products, encoder feedback features and much more, please visit our new video library.
  • For more information on our IP65 rated product, see our IP65 product overview video.

Modbus® is a registered trademark of Schneider Electric, licensed to the Modbus Organization, Inc.