At the end of the article, there are 55 practical case materials.
Introduction: In automation equipment, the automatic control program is the basic function for the normal operation of the equipment. Since the logic of automatic control is essentially “start condition” result “end condition”, this article uses Siemens S7-1200 PLC and Inovance PLC to write programs, allowing for a comparison of the similarities and differences in programming these automatic control programs!
1.Control Requirements:
There is a liquid mixing system with two feed pumps (PumpA and PumpB), a mixing container, a stirring motor, and a discharge valve.
The process is as follows: First, start PumpA and PumpB for feeding. After feeding is complete, start the stirring motor to stir for a certain period, then open the discharge valve to discharge. After completion, proceed to the next cycle until the stop button is pressed, at which point everything stops.
Programming for S7-1200 PLC
(1) Create a new FB block and define the interface variables.
(2) Program Analysis
Program Segment 1 assigns the step variable value to 1, indicating the “first” step.
Program Segment 2 checks if the step value equals 1 to open both pumps. When both sensors are activated, the step value is modified to “2“, executing the second step action.
Program Segment 3 controls the discharge valve, with a discharge time of 3 seconds. After the time is up, the step value is modified to “3“, executing the third step action.
Program Segment 4 controls the discharge valve, and upon meeting the conditions, it jumps to step 4
Program Segment 5 is for the loop and stop function.
Programming for Inovance PLC
(1) Create a new FB block and define the interface variables.
(2) Implement different functions based on different step sequences; the programming approach is quite similar to Siemens, so it will not be elaborated here!
(3) Call the FB block and assign addresses.
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