Feed Mill Automation Case Study: Mid-South Milling
Situation: Mid-South Milling operates two feed mills in the United States: Memphis, TN and Kansas City, MO. Both plants have complex operations that were running old ACECO hardware, which was no longer available. This required both plants to upgrade their control system software and PLC panels. The customer asked that Comco reuse as much of the existing control wiring as possible (instead of providing all new PLC panels) to minimize downtime and electrical cost.
Both of these control systems required a significant number of programming customizations. Mid-South also has a third-party AS400 legacy system that is central to their operations. Comco was able to integrate with the AS400 system to automate plant data, processes, and inventory. This required a large amount of custom programming and extensive testing to ensure reliable two-way communication.
These projects were both challenging with several unique requirements. Commissioning had to be near-perfect: only a very minimal amount of downtime could be allocated by the customer due to production commitments.
Comco Solution
Comco provided complete turnkey control system solutions from electrical/control design services to implementation to post-commissioning support at both plants. Comco spent a significant amount of time planning the PLC and software changeover internally but also with the customer and the electricians.
Comco Solution
Control System – Comco implemented its custom Feed Mill control system with custom HMI graphics at each site to maximize operations. The HMI at both sites needed to have the overall same look and feel as but customized to each site’s flow diagram and production needs. The HMIs designated separate transactions (ie: receiving, batching, loadout, etc.) by color for easy visual differentiation. Finally, the system audit log accurately tracked security log-ins, user actions, system processes, and material transactions.
Plant Processes in the Mid-South Control Systems – Receiving, Transfer (with optional Grinding), Batching/Blending, and Loadout.
Engineering Services – Comco provided electrical design services such that all drawings were clear and accurate for electricians to follow on site. Comco also provided the design for all new PLC panels. Comco engineering spent a significant amount of time with the Comco software team and the site electrician to cover all details.
PLC Panels – All new PLC Panels provided were CSA/CSAUS certified, designed with the best components, and tested comprehensively prior to shipping. Loose parts were provided to the site electrician where possible to allow the customer to reuse control wiring that had been run for the ACECO system.
Third-party data integration to the AS400 system – Comco was able to effectively integrate its custom control system with the legacy AS400 system using a Web API and data bridge. This integration included inventory, ingredient, product, receiving job, batching job, and loadout job imports as well as inventory, receiving job, transfer job, batching job, and loadout job exports.
Commissioning – Comco provided a simulation environment of the control system to each site so that remote operator training could occur prior to commissioning. During commissioning, a team of Comco programmers was sent to site to provide system installation services, comprehensive system testing, electrical support, and operator training. On-site training included system usage and PLC troubleshooting. All I/O points were fully tested to the end devices and all routes and interlocks were tested for the appropriate control system reaction alongside the electricians and operations team.
Comco Value-add
Comco has provided a number of benefits to Mid-South over the years:
- Comco team members were able to support the legacy ACECO systems until the upgrades were authorized.
- Reusing existing control wiring for the changeovers provided significant savings to the customer.
- Pre-commissioning training using a simulation environment provided operator confidence prior to installation.
- Reliable integration with the AS400 system was critical for operation of both plants.
- 24/7 support has been very important to Mid-South with their tight production schedules.
Nathan Pappas
President - Mid-South Milling
