DMC’s customer required that their current brewing system be upgraded from multiple timers, PID controllers, and manual valves. The previous system required that the operator monitor timers and adjust PID controller set points manually. The client had selected to use a Unitronics Samba PLC/HMI for the upgrade due to its price point and ease of use.
DMC began by working closely with the client to document how the operator manually controlled their brewing system. This document served as a basis for creating PLC sequences and defining what parameters are necessary for a recipe.
Several user groups (supervisors, maintenance, and operator) were created with the Samba 7’s integrated user management. Only supervisor users could modify existing recipes. Maintenance and supervisor users could modify machine parameters (e.g. PID gain, temperature tolerances). All three groups (supervisor, maintenance, and operator) could select and execute existing recipes.
Recipes are managed using the Samba 7’s built-in recipe management system. When a recipe is selected, there are multiple methods available to choose from: immediate start, time-delayed start, or start at a designated time. Once a recipe is executed, devices are automatically started as needed and temperature set points are automatically updated. The temperature of the kettles was controlled by pulsing heaters according to the PID control loops executing on the Samba 7.
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