When it comes to quiz buzzers, everyone is familiar with them. Quiz buzzers are generally designed and implemented using microcontrollers or dedicated control boards. For those involved in industrial control and learning about industrial control, have you ever thought about how to implement this using the PLC in your hands? If you haven’t thought about it, that’s okay. This article will guide you through the thought process and practical implementation.
1. Control Requirements
(1) There are 3 contestants: Contestant 1 – Xiao Ming, Contestant 2 – Xiao Fang, Contestant 3 – Xiao Hong.
(2) The host must press the buzzer confirmation button before a contestant can buzz in; otherwise, an alarm will sound.
(3) The buzzing time is 10 seconds; if the time expires, the buzz-in is invalid, and any further attempts will trigger the alarm.
(4) If a contestant buzzes in first, subsequent buzz-ins are invalid (first come, first served).
(5) The alarm will sound for 10 seconds, after which it will stop.
2. PLC External I/O Address Distribution Table (External Button Control)
3. PLC External Hardware Wiring (ST20)
4. Program Design
Step 1: (Host Confirmation and Timing Control)
Step 2: (Buzz-in Control for Xiao Ming/Xiao Fang/Xiao Hong)
Step 3: (Buzz-in Alarm Control)
5. MCGS Interface Design
Step 1: (Adding Variable Addresses)
Step 2: (Interface Design)
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