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Scale Model Dark Ride

For my Show Control and Networks class, our final project was to build a scale model dark ride in teams of four. In our group, we had two engineers, a lighting student, and a sound student. Specifically, I was the team member with PLC experience. We were given a line following cart, four iMacs, a PLC, 5 LCD panels, 6 speakers, and 6 RGBW lights. Our show was time based with a star topology. We programmed lighting, sound, video, and cart control cues in QLab using MIDI message protocol.

I set up the ride area with the speakers and video screens positioned to create an environmental and location specific experience. I put together the voice over using text-to-speech, programmed all of the sound cues, and found our copyright free recording of Ride of the Valkyries.

Originally, we wanted to use the PLC to control the starting of the ride and incorporate break beam sensors wired to the PLC to make the cart start and stop at each scene. Unfortunately, we faced unexpected issues that were out of our control when communicating between the control computer and the PLC. I troubleshooted the PLC program with my professor, but he was unable to adjust his program in time for our presentation. To get a functional show, we pivoted last minute, scrapped the break beam sensors, and reprogrammed all of our cues to fire relative to each other. With the battery dying in the cart, our final system was not as we had planned, but we were all very proud of our finished product and the challenges we overcame.

Flight of the Valkyries recording via Lud and Schlatt's Musical Emporeum on YouTube


In this lab, I worked on a team with another student (Ashley Kikos) to build and wire a PLC according to a provided wiring diagram. Together we wrote ladder logic code to make it functional.

Step 1: Building the PLC

At the top of the PLC box is a key switch that controls the power supply, e-stop, and a yellow light indicating power supply.

Images showing the wiring of our PLC and the buttons.

Step 2: Programming

Hardware configuration of our PLC in Productivity Suite software

Using the Productivity Suite software from Automation Direct, we wrote ladder logic code to achieve the functionality in the video below. We utilized normally open/closed contacts, rising/falling edge contacts, different types of outputs (flashers, counters, etc), and techniques such as latching.

Step 3: Testing

Video description: Pressing the green button puts the PLC in enabled mode, which is shown by the lit green light. Each press of the yellow button increases the value of a counter by one. State: Counter is less than target Feedback: Blue light is on, yellow light is off The yellow button is pressed until the counter is equal to 10. State: Counter is equal to target Feedback: Solid yellow light is on, blue light is off The yellow button is pressed two more times setting the counter to 12.  State: Counter is higher than target Feedback: Blue light is on, yellow light is flashing Pressing the blue button decreases the value of the counter. It is pressed twice. State: Counter is equal to the target value Feedback: Solid yellow light on, blue light is off. The counter is increased and decreased a couple more times and finally, the green button is pressed which resets the counter to zero. State: Counter set to zero Feedback: Blue light is on, yellow light is off By pressing the red button, the PLC is put into disabled mode. The red light is on and when the blue and yellow buttons are pressed, the counter value does not change.