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Last time we saw how a solenoid valve operates a pneumatic actuator in a jelly depositor in a food manufacturing plant. The operation was manual. In other words, an electrical switch had to be thrown by hand each time to get the solenoid to work. This can be rather tedious, when you consider the thousands of pastries that must be filled on each production run. Now, let’s see how the solenoid can be automatically turned on and off by an industrial control system. In food manufacturing plants, industrial control systems are typically made up of programmable logic controllers, otherwise known as “PLCs.” The PLC is an industrial computer that is used to control equipment like conveyor belts, motors, pumps, robots, and solenoid valves. The PLC is connected to Input/Output Modules, or “I/O Modules.” The I/O modules act as an interface between the computer and the equipment in the plant. As such, they contain a means to connect electrically to the computer and the plant equipment. In the case of our solenoid valve, the PLC computer program would turn the valve’s solenoid on and off. Whether it is turned on or off depends on the computer program’s timing and/or external sensors and how it feeds in conveyor belt/pastry position data to the PLC. The result is the automatic depositing of jelly filling as each pastry passes by the depositor nozzle.
The Depositor’s Industrial Control System
That wraps things up for our blog series on depositors. Next time we’ll move on to a new topic. Copyright 2018 – Philip J. O’Keefe, PE Engineering Expert Witness Blog ____________________________________ |
