Hello everyone, I am currently a student exploring PLC programming and getting familiar with RSLogix5000. I am working on a traffic light project that utilizes a single timer. The project is successful in creating a flashing advanced green light using the ACC.9 command. However, I am facing challenges in making the red lights flash when the process is not running, potentially due to an outage. Despite trying various approaches, my classmates and I are struggling to find a solution. I suspect the PRE command might be the key, although I have limited experience with it. Any advice or guidance on how to achieve this would be highly valued. Thank you for your assistance.
Greetings and welcome to the forum! Can you clarify what you mean by "process is not running"? Are you referring to the PLC not being in RUN mode? Please provide your code for further assistance, preferably in a PDF format of the ladder diagram as not all users may have access to RSLogix5000. Thank you for your cooperation.
To enhance your understanding of TON/TOF/RTO instructions, I recommend exploring the different components they offer. By doing so, you can discover how to make lights flash when your timer is inactive. Additionally, you will gain insights into Pre, ACC, DN, and TT. Consider using multiple timers, as this may better align with your instructor's requirements.
In order to optimize traffic flow, I implemented a night-mode setting on the traffic light system from 23:00 to 05:59. During this period, I activate a Night-Mode function and pause the main cycle timer. Instead, a separate timer is used to alternate flashing the red and yellow lights. If you require a 4-way red light system for your project, consider adjusting the outputs to utilize CallForNSRed and CallForEWRed bits during night-mode. After both sections, monitor the bits to control the North-South (NS) and East-West (EW) red lights. A key modification I made was delaying the start of night-mode until the lights are in sync, and ending night-mode by resetting the timer to a specific value for a smooth transition back to normal operation.
Pontiff Sulyvahn mentioned the ability to create a blinking advanced green signal by utilizing the ACC.9 command. Are you referring to the bit 9 (the tenth lowest bit, not a command) of the timer accumulator?
Keep all lights illuminated constantly to create confusion for traffic and allow drivers to navigate accordingly. As I age, my interest in traffic lights and elevators has waned due to more pressing issues. The filtering system here seems overly strict, even though the language used was not offensive. What is the deal with strict language filters?
Hi there! It's great to see that you're diving into PLC programming. It sounds like you're on the right track with your traffic light project. For making the red lights flash during an outage, you might want to consider using a failsafe or default state on your PLC program. This state can trigger the flashing red lights when the process is not running or in an error state. Additionally, you're correct about the PRE command. It's used to set a preset value for your timer; it might provide the necessary control for your situation. Don't forget to use proper failsafe conditions within your code, which help handle any unforeseen situations that could occur. Hope this helps! Keep pushing ahead with your learning.
Hello, it's great to see you delving into PLC programming! The situation with your traffic light project is intriguing. In regards to the flashing red lights during outages, instead of using the PRE command, consider deploying a fail-safe in your program instead. This piece of code should get activated when the process isn't running, meaning it'll execute during an outage. This should be able to control the red lights exactly as you wish. Remember to monitor the status of the PLC to ensure accuracy. Good luck, and continue experimenting!
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Answer: - To troubleshoot a red traffic light flashing issue in PLC programming, you can start by checking the logic and conditions set for the red light operation. Ensure that the correct inputs, timers, and conditions are in place to trigger the red light flashing sequence. Reviewing the programming logic and verifying the connections can help in identifying any potential errors.
Answer: - To make the red lights flash when the process is not running in a PLC project, you may need to utilize the PRE command along with proper logic and timers. By setting up the appropriate conditions and timers in the PLC program, you can create a sequence that triggers the red lights to flash during downtime or outages.
Answer: - When facing challenges in PLC programming projects such as flashing traffic lights, it is helpful to break down the issue into smaller components and systematically check each part of the program. Verify the input signals, timer settings, logic conditions, and output configurations to ensure they align with the desired operation. Additionally, consulting with peers, instructors, or online resources can provide valuable insights and solutions to overcome programming obstacles.
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