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ABC-Illinois Excellence in Construction Award: Corn Unloading Project


Wesa Automation is pleased to announce that we have been awarded the Associated Builders and Contractors-Illinois Chapter 2017 Excellence in Construction: Award of Excellence for the Corn Unloading Project. The objective of the project was to unload a 110-car unit train in 2 shifts, from a new rail unloading area, which is divided into three compartments. Each compartment has a cross conveyor designed for about 15,000 BPH (bushels per hour), and the three cross conveyors discharge into a common belt conveyor, which carries corn from the unload area across the street to the bucket elevator at the base of the silo to be carried to the top of the silo. As part of the scope of work, we provided a new Allen Bradley PLC 5000 control system and complete programming for the new corn unloading facility.

There were approximately 140 I/O points that needed to be wired to two separate PLC systems, including zero-speed switches, hatch limit switches, plugged chute sensors, baghouse blow down modules, etc. Half of the system went to an existing PLC 5 architecture, and half went to the new panel that our in-house UL-Listed and CSA-Certified panel shop built. MKD Electric also provided all control wiring for approximately forty 3-phase, 480 Volt motor starters located in new motor control centers.

Due to the fact that a good portion of the PLC program had to be loaded onto a live processor that was running a large wet mill facility, our engineers spent almost two months developing the code to run a sequenced start and a sequenced stop routine for 18 motors. These sequences had to be able to handle unexpected events and safely run a controlled shutdown procedure. We reviewed the progress of the programming frequently with the client’s engineering team, and when we were ready to start testing, we ran a simulated run at our testing lab at our main office and shop to ensure the program was stable enough.

In the event that the PLC encountered a major fault and shut down when we loaded our program, we had a 5-minute window to recover without causing a costly plant shutdown. To prepare for this, we planned to have extra client staff on site ready to react immediately if a shutdown did occur in order to assist with bringing the system back to running ASAP. Due to our preparations, we were able to load the program live without any issues.


ABC-Illinois Chapter is a trade association dedicated to serving construction professionals within the state of Illinois. They promote free enterprise by advancing the merit shop philosophy in the construction industry through education, advocacy, and business services.

The Excellence in Construction Awards recognizes outstanding construction projects throughout the state.

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