Selecting Motor, Drive, Controller Combinations

It’s easy to find advocates who support the idea that servomotor, drive, and controller combinations, combinations work best when sourced from a single provider. It’s also not difficult to find those who will argue it’s better to select best-of-breed components and integrate them for optimal performance.

That’s why the question of which path is the best to take—single vendor or best-of-breed—continues to reverberate across industry. Automation World received several questions about this very topic in response to a recent survey. 

To help answer this question for our audience, we connected with Eric Roggeman and Greg Dieck of Omron Industrial Automation—a supplier of automation technologies ranging from sensors, control, and safety components to motors, drives, robotics, and power supplies—for an episode of our “Automation World Gets Your Questions Answered” podcast series.

Roggeman began the interview by noting motors and drives are most often purchased together, with controller preference often being the biggest factor driving the decision. The exception to this rule occurs when the application involves the need for a special type of motor, for example, an explosion-proof or hygienic motor.

Driven by controller preference, “the advantage, when using a single supplier, usually comes to down to the software,” said Dieck. “If you have a single software package from one vendor, it’s easier to build and maintain a single tag database, and the learning curve with a single software package is easier. It’s also easier to replicate machines in the field when you’re using one software package for drive parameters. And you can more easily tune multi-axes (with gantry or cartesian systems) for better throughput and to avoid waste.”

Because drives are typically connected to the controller, rather than the motor, these two components tend to be purchased from the same supplier. “This helps simplify communications between the servo and controller,” Roggeman said, “it makes the connection more plug and play.”

Speaking of communications across servomotor, drive, controller combinations, Roggeman advised selecting devices so that the same protocol is used across all three components. As part of this communications review, be sure to “consider encoder communications—such as SSI, EnDat, and quadrature,” he advised. “[Encoders] talk to the drive differently to ensure positioning is correct, so it’s important to ensure all three components are on same page [with these communications]. Also be sure to consider the cabling and connectors between all three to make sure everything fits together.”

Dieck added that, when collecting data from a controller, there are multiple networks you can use. “But when it comes to motion applications, you need a high-speed, deterministic network between the drive and controller,” he said.

Another advantage to having a single supplier for your servomotor, drive, controller combinations is troubleshooting. “When you’re troubleshooting a system sourced from the same suppler, the controller will recognize error handling for the drives,” said Dieck. “[This means] you can bring centralized error handling into the machine. This is key for part failures, but you can also add in machine specific errors to warn maintenance about pending problems. This is especially helpful with OEE (overall equipment effectiveness).”

Outside of the special applications Roggeman and Dieck noted—such as the need for explosion-proof or hygienic motors—are there any instances where best-of-breed component selection is preferred over a single-source provider? Roggeman said the issue of motor size requirements can make a best-of-breed selection necessary. “If you have a controller and drive that works well together, but the motor you need—maybe one with a higher horsepower—is not offered by that brand, you will need to source the motor from another provider. This is also encountered if you need a specialty motor, such as a direct drive or pre-geared motor that may not be offered by your drive and controller provider.”

As for the driving factors behind these buying decisions, Dieck said that performance is more typically the most important consideration—even overriding cost concerns.

Roggeman added that, with the increasingly litigious nature of society, safety is becoming an issue of equal importance to performance in these buying decisions. More users want safety aspects built into the projects from the onset, he said.