Application of Programmable Logic Controllers for Automation of Bottling Line Operations at a Beverage Plant in Ogun State

Beverage bottling operations at medium-scale manufacturers in Ogun State, South West Nigeria, frequently rely on relay-logic-controlled and semi-manual production line operations that are inflexible, difficult to troubleshoot, and incapable of meeting modern production efficiency standards. This study presents the application of Siemens S7-1200 programmable logic controllers to automate a complete bottling line encompassing bottle rinsing, filling, capping, labelling, and conveying operations at a soft drink plant in Sagamu. Ladder logic programs were developed and tested using TIA Portal software, incorporating sequential function chart programming for the main production state machine and function block diagrams for auxiliary processes including CIP cleaning cycle control. Operator interaction is provided through a 10-inch Siemens KTP1000 basic HMI touchscreen panel. Production line cycle time was reduced from an average of 4.8 seconds per bottle under the previous relay-controlled system to 2.9 seconds per bottle following PLC implementation, representing a 39.6 percent throughput improvement. Electrical fault incidents attributable to relay system wiring failures dropped from an average of three per month to zero over the six-month post-implementation period. Training for eight plant electricians and technicians was delivered over a five-day structured programme. The study documents the project management timeline, commissioning challenges, and lessons learned in executing the automation upgrade within the operational constraints of a continuously producing plant. Keywords: PLC automation, bottling line, Siemens S7, beverage manufacturing, Ogun State