Hello everyone! This is my first post on this platform, and after observing for a while, I’m excited to join the conversation. As a beginner, I've encountered a challenge with one of my initial projects. I suspect that the solution is straightforward, but I might be overcomplicating things. My project involves a combining gate designed to merge bottles from two separate conveyors into one streamlined path. This seems simple in theory. However, there’s always a catch! Currently, everything operates smoothly, but when both infeed lanes become congested, the gate fails to pivot between the two sides. By the time there’s demand on the single lane, the ready condition for that same infeed lane is already met, causing the cycle to repeat, with the other lane becoming jammed. To clarify my setup, I’ve included a sketch. Here’s how the system functions: - Stops on Infeed Lane 1 (LN1) and Infeed Lane 2 (LN2) are closed, allowing bottles to accumulate on both lanes. - When the bottles reach the Proximity Sensor (PE) on LN1 (I:1) and LN2 (I:2) for a predefined duration, the Ready Bits for either LN1 or LN2 are activated. - If there is demand on the output lane LN3 (I:7), the gate swings toward the lane that signals as ready first. However, it can only pivot if the PE Gate Clear (I:5) is activated. The gate is designed for a single lane operation using a spring return solenoid. - As the Proximity Switch determines that the gate is in position, the Stop on the corresponding lane (O:1 or O:2) opens, releasing the bottles. - Once the bottles reach the PE for Lane 3 Stack Control (I:6), the Stop on that lane closes, awaiting the next demand from Lane 3. The issue arises when bottles begin to stack up again on the lane that just fed Lane 3; the cycle resumes on that same lane, disregarding the other lane that had previously been ready. There is a gap created by the incoming bottles on the infeed lanes (backup pressure gates), which I could potentially exploit to implement a latch/unlatch mechanism for the ready/not ready states. My goal is to ensure that the gate swings to the lane that is ready first. However, I haven’t previously worked with FIFO blocks or counters, nor have I successfully utilized two timers to compare their statuses. So far, my attempts have mainly involved basic logic. I would greatly appreciate any insights or suggestions on how to resolve this issue! Thank you in advance for your help!
In similar scenarios, I have implemented a solution using two timers alongside a comparison mechanism to determine which timer has been active the longest. Additionally, I have executed a comparable control strategy where I set limitations on how long one supply lane could operate before allowing others to take their turn. Without access to your specific code or the actual flow of your product, it's challenging to offer precise recommendations. If your organization permits, please consider zipping your RSLogix file and attaching it to your post or include relevant screenshots to give us a clearer view of your logic design. To do so, click the "Go Advanced" button at the bottom of the reply interface, which will reveal the "attach files" option along with the necessary dialog. Be aware that the forum has restrictions on file types and image sizes, so if you encounter any difficulties, feel free to reach out for assistance. We are glad to have you in the forum!
Hello and welcome to the forum! After reviewing your setup, I suggest modifying your logic to maintain a condition that "holds" the recently called lane, even if it becomes ready again. This can be achieved until the other lane has successfully moved its bottles. Think of it as a flip-flop bit scenario, where you incorporate a specific gate position. This logic can function with conditions like equal (EQU) or not equal (NEQ), ensuring that the bit activates only when the gate is in the intended position. I’ve successfully implemented EQU/NEQ instructions for safety gates in A-B programming for robotic cells, and it performed quite well. You can expect some experienced professionals to assist you promptly. Once again, welcome to the community!
Thank you all for your prompt responses! I appreciate your support as I share the attached Ladder document for your review. Please bear in mind that this is not my usual area of expertise, so any assistance would be greatly appreciated.
I would like to offer some suggestions, such as utilizing a counter triggered on the rising edge of B3/11 with a preset value of 1. With this setup, if the counter’s accumulator reads zero, lane 1 would be selected; if it reads one, lane 2 would be chosen. I began editing the code to incorporate this concept, but I’m concerned about potentially disrupting other parts of your logic that I don’t completely grasp. I must say, your logic structure appears quite solid. Each address is well-commented, which definitely earns you extra points in my book!
Thank you! I’m excited to give this a try today. I’ll make sure to keep you posted with any updates!
Welcome to the forum! It sounds like you've got a solid grasp of the basics, but I can see how the congestion issue is causing a headache. Have you considered implementing a priority system for the ready lanes? By using timers or counters to monitor how long each lane has been in a ready state, you can create a logic that favors the lane sitting idle the longest when both are ready, essentially preventing the gate from getting "stuck" cycling back to the busy lane. This way, you can ensure that the gate identifies the best option dynamically, which might alleviate some of the traffic jam issues you’re facing. Good luck, and I’m excited to see how this project evolves!
Welcome to the forum! It sounds like you're tackling a really interesting project, and it's great that you've provided such detailed information. From what you've described, it seems that implementing a FIFO queue could definitely help manage the flow effectively between those lanes. You might also consider using a priority logic system that allows the gate to favor the lane with the longest waiting queue when both lanes are simultaneously ready. Pairing that with a debounce mechanism could prevent unnecessary cycling when one lane is overwhelming the other. Keep experimenting with the timing and maybe even simulate the process to visualize what adjustments might work best. You're on the right track, and I’m sure you’ll find a great solution!
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