There are two kinds of systems that are easy to use: Inherently simple equipment, and more highly engineered "total solution" systems. Here, we'll discuss the latter — and how to make sense of the myriad of options and features available to machine builders.

Let's say an engineer has the luxury of abstracting motors into simple devices that create motion from a voltage signal. Well, brush motors, despite their wearing parts, are certainly the easiest to setup and control. "Applying sufficient voltage to the terminals causes the shaft of the motor to rotate for simpler control schemes," says Patrick Dell, applications engineer at MicroMo Electronics, Inc., Clearwater, Fla. Indeed, open-loop speed control requires little equipment — sometimes just a battery is enough. "Small brushed motors run in many applications requiring little more in the way of control," says Dell. To control motor torque, however, more complex circuitry is required to regulate the current in the motor windings.

"Now, sometimes ac inverters have open-loop vector modes that works better pushing simpler constant-torque loads such as conveyors — in addition to adjustable voltage/frequency output that works well with variable torque loads, such as centrifugal pumps and fans," says John Malinowski, Baldor Electric Co., Fort Smith, Ark. Increasingly, there is a push towards these "smart" components that incorporate multiple logic functions. And with designers today being asked to absorb more engineering responsibilities from their customers, these systems can be very helpful. "OEMs can't save money by acting as integrator. With the algorithms in many devices today, software can automatically program setup at a cost of $200 or less," says Rich Mintz, U.S. products manager at SEW-Eurodrive, Lyman, S.C. He argues that no OEM could engineer a setup for so little. Integrated, preengineered systems can save weeks of programming and debugging complicated machine control applications. When designers purchase separate motors, encoders, reducers, and brakes, OEMs must act as integrators and are tasked with the sometimes-difficult job of making everything work together. "When, for example, gearmotor and control are a matched package, with self-tuning algorithms and application routines, then it can take as little as two minutes to set up a system," says Mintz.

In any case, it doesn't make sense to look at any system apart from the mechanical or electrical perspective. "Just as one can never describe an elephant by looking only at an ear or a leg, looking at a motor in isolation never gives you the right solution. You have to look at the entire system and what you're trying to achieve," explains Mintz. "When you stop seeing standalone components, then you can achieve the greatest precision and efficiency in performance," he adds. "The motor is only a tool to make something happen; what you're really trying to control are parts to which it's connected.

If a PLC, motion controller, I/O, motion network, drive, and motor each require significant custom programming and record keeping, the control architecture is less easy to use. "On the other hand, advanced auto-tuning algorithms are invaluable to commissioning the axis as quickly as possible," says Adam Shively, product manager at Rockwell Automation, Eden Prairie, Minn.

Some controls operate right out of the box; simply plugging in motor parameters allows these controls to autotune. "New guys don't realize that setting up a control was once difficult and painstaking, sometimes taking three or four hours," says Jeff Lovelace of Baldor Electric Co. The software provided with controllers today greatly influences how easy a system is to setup, control, and troubleshoot. "Good setup wizards allow users to configure systems without digesting a PDF treatise," says Dell.