Hello everyone, I have developed a method for gradually increasing the PWM signal on the Micro 820. As I am new to ladder logic, I am unsure if this approach is effective. When the xmotoron signal is activated, it should cyclically activate pin 6 unless both the home and end proximity sensors are simultaneously triggered, all while considering the direction. Each time xmotoron is triggered, it should go through the acceleration process until xaxisspeedmax is achieved. Any feedback on this would be greatly appreciated! Thank you. You can find more details at the following link: https://1drv.ms/i/s!AmGu4mSmjSxdgppQqs7BPwx9yN5-hw?e=uUFIHB. Best regards, DI.
I am unfamiliar with the 820 model, as I have never used one before. However, in Mitsubishi PLCs, the PWM instruction is only compatible with transistor outputs. If your PLC is equipped with transistor outputs, the PWM instruction should function properly. It is important to note that the PWM instruction may not support interrupts, which are necessary for generating fast pulses. In such cases, the instruction may only respond accurately to pulses that are slower than the scan time, as well as the time required to switch the output on and off.
1) The code contains errors that may prevent it from functioning properly. The writing to the Boolean accelmotor in Rungs 3 and 4 may cause issues, such as the timer never expiring as intended due to the order of operations. Additionally, the CTU may not complete if accelmotor remains high for multiple scan cycles. 2) It is important to note that the ENO of the PWM instruction does not control the PWM output. Any instructions following the PWM instruction on Rung 2 may not work as expected. It is advised to refer to tutorials, such as the one by Tim Wilborne on YouTube, for guidance on handling inputs and outputs. 3) If parameters for frequency and duty are constantly changing while the PWM instruction is enabled, the PWM output may not function correctly. In some cases, toggling the enable button may be necessary to update the PWM output based on the new parameters. For a potential solution, consider implementing a Start/Stop Circuit pattern in the code, as explained in the provided link. This pattern may help manage inputs and outputs effectively. Additionally, refer to the mentioned video tutorial for assistance with handling specific inputs.
Last chance: While the Micro800 and CCW line may suffice for basic tasks, they are limited in handling more intricate operations. If you're attempting something complex beyond simple relay logic, there's a possibility it may not function as anticipated. It's worth noting that finding a suitable workaround may be necessary for your project. Join our forum for more insights.
Hello Brian, thank you for your response. I initially followed Tim's video but made some errors. I have addressed all your comments except for (2.2). I hope that making discrete frequency changes at specific times will solve the issue you encountered. Please take a look at this image and let me know if it seems to be a better solution. I will create a separate code to deactivate the xmotoron input using the home/end proximity sensor. You can view the image here: [insert link]. Thank you, DI.
In the updated code, the bit accelmotor2 may only remain active for one or two scan cycles after the xmotoron is released. Refer to comment 1.2.2 in my previous post for more information. It is essential to understand the scan cycle in PLC programming as it serves as a clock that dictates time-related operations. By mastering the scan cycle, you can easily identify issues in your code. If you find yourself using multiple instructions to perform a simple task like incrementing a value, it is advisable to consider a different approach. Take a look at the code exemplified in the image below, which implements the Start/Stop Circuit pattern. Note the clear path from the Start/Seal-in branches through the only Stop Condition (XIO CTU_1.Q) to the Run Coil (OTE accelmotor). Avoid placing conditional instructions that may disrupt the circuit in this path, as every instruction in the rung is evaluated on each scan cycle. This process happens rapidly, similar to a frequency of 1kHz. Have you worked with programming languages like C, Python, Java, or BASH before? Understanding PLC programming requires a different mindset. PLCs operate similarly to GAWK or infinite loops in Perl or Python. Familiarize yourself with these concepts to enhance your PLC programming skills.
Hey DI, welcome to the world of ladder logic! From what I understood, it seems like you're on the right track. Accelerating the PWM signal until xaxisspeedmax is achieved, and then holding it there unless the home and end proximity sensors are triggered is a smart way of controlling the speed of the motor. Be sure to add in failsafes though so that the motor isn't damaged in the case of an error. Also, consider implementing a gradual deceleration phase to ensure the equipment is not put under unnecessary strain. Good luck and do keep us posted on your progress!
Hi DI, it sounds like you're on the right track with your design, but I do have a few suggestions. It would be useful to incorporate ramp-up and ramp-down code to ensure smooth acceleration and deceleration of your motors. This could help prevent sudden stalls or potential damage to the motor and equipment. Also, consider adding 'motor running' status checks throughout to make sure you're not trying to drive an already moving motor. Lastly, don't forget to add error handling in case of sensor failures. Ladder logic can be tricky, so further improvements to your design will come easier as you gain more experience. Keep at it, you're doing great!
Hi DI! Your approach sounds promising, especially the gradual PWM increase for acceleration—it can really help with smoothing out the motor's start-up. Just make sure that your logic handles the simultaneous activation of both proximity sensors effectively, as that could cause issues with directional control. It might be helpful to implement a safety timeout or error state to prevent unexpected behavior when those sensors are triggered. Looking forward to seeing your progress!
Hi DI! It sounds like you’ve put a lot of thought into your PWM control method, and it’s great that you’re considering acceleration up to the maximum speed—that will definitely help with wear and tear on the motor. Just make sure you include some debounce logic for the proximity sensors to avoid any false triggers that could interfere with your operation. Also, testing your setup in smaller increments can really help you identify any tweaks needed in your ladder logic. Can't wait to see how it works out!
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Answer: - To gradually increase the PWM signal on a Micro 820, you can develop a method where the xmotoron signal cyclically activates pin 6 unless both the home and end proximity sensors are simultaneously triggered, considering the direction. Each time xmotoron is triggered, it should go through the acceleration process until xaxisspeedmax is achieved.
Answer: - To ensure effective activation of pin 6 on the Micro 820, make sure to properly handle the xmotoron signal and consider the activation conditions such as the home and end proximity sensors, as well as the direction, in your ladder logic programming.
Answer: - You can find more details and information about the method for gradually increasing the PWM signal on the Micro 820 by visiting the link provided: https://1drv.ms/i/s!AmGu4mSmjSxdgppQqs7BPwx9yN5-hw?e=uUFIHB shared in the discussion thread.
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