PLCs Help the Show Go On

How industrial automation plays a leading role in show-biz scenery.

In February 2020, Control Design posted a website article by Ryan Poethke of Showman Fabricators, titled Motor Control When Hanging From The Ceiling. Here’s a summary, click on the link above for the full text.

Industrial automation can play a role in many situations beyond typical machinery and manufacturing applications. For instance, theatres need automation technology to operate various scenery and lighting elements.

Showman Fabricators is a studio set designer/builder and needed a solution to configure and control 20 individual ceiling-mounted integrated servo motors, used to hoist scenic elements like large light rings to specified elevations. They took advantage of the latest developments in IP-enabled motion and programmable logic controller (PLC) technology to make this possible.

Toil and Trouble

The servo motors in question are 25 feet above the floor, and each use USB communication (with about a 16-foot cable connection limit) for reprogramming by PC-based software. It would not be practical for technicians to access each of the motors using scissor lifts and ladders. Each servo motor also needed an associated PLC for commanding its motion profile from a central location.

Strong Reasons Make Strong Actions

To overcome these challenges, the team took several steps. First, they proved out a USB device server which they could connect locally at each servo motor via USB, and then networked the servo motors together using the wired Ethernet already in place for PLC-based control.

Second, they designed and fabricated 20 standard control cabinets, one for each servo motor, containing the:

Each cabinet effectively has two IP addresses: one is the USB device server targeted by a PC with the servo configuration software, and the other is the AutomationDirect BRX PLC accessed by a human machine interface (HMI) touchscreen for motor control. All cabinets are linked in a linear fashion with wired Ethernet.

All the World’s a Stage

For the Showman Fabricators team, AutomationDirect played a key role for enabling automation of their theatre equipment. Although industrial automation may seem to be a very specialized field, many end users in all sorts of industries can take advantage of reliable and economical AutomationDirect products to provide digital and electrical solutions for a wide variety of applications.

Figures all courtesy of Control Design