PLC code design

Since we are now moving into the PLC code development, we need to start looking at a design. Normally, the design of the PLC code is done in conjunction with the HMI design; however, we designed and implemented the HMI first because we are completing all the steps ourselves and this is an education project. Therefore, as stated before, it is common and best practice to perform the whole design phase for both the HMI and the PLC code at the same time if possible. Again, we only implemented the project the way we did so that we can have an HMI ready to start testing our PLC code.

To keep the design simple, let’s break the project down into the following function blocks:

1. Oven: This function block will handle turning the oven on and off, as well as ramping the oven up to temperature.
2. Alarms: This function block will trigger error, warning, and info alarms.
3. Door: This function block will be responsible for locking and unlocking the oven door.
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