Hello everyone, I am in the process of creating a proposal for a control system for a bus effluent retention tank extractor. The system consists of 8 modules in the field and 1 plant room. Each module has 2 operating modes: 1. Pressing the Extract Only button closes a VFC in the main panel, activating a standalone pump set, and opening the module extraction valve for a set time period when the vacuum reaches the necessary level. 2. Pressing the Extraction & Rinse button follows the same process, but also opens a separate rinse valve in the module for back flushing the tank before another extraction cycle. For the proposal, I am considering using 1 M221 PLC in the plant room that communicates with the 8 M221's in the field via the MODBUS protocol as distributed IO. This approach avoids the need for extensive cabling to each module (approximately 300m to the end one) and eliminates the need for a main control panel with numerous terminals and expansion modules on the M221. Has anyone implemented a similar system before? If so, I would greatly appreciate any advice on where to begin. Thank you.
Explore their product selector tool: Customize your control system with a Programmable Logic Controller (PLC) and I/O modules. Easily select your PLC and PAC solution in just three steps using the Modicon PLC Configurator online. Configuring your PLC has never been quicker. Visit www.se.com to get started. Upon reviewing the options, you'll notice that they suggest using a TM3 bus coupler that can connect via serial or Ethernet. Are there reasons for placing a PLC in each module? Perhaps the module has a standalone local function that needs to operate even when the network is down. Or maybe you prefer to have a more advanced PLC in the main panel instead. The setup you're outlining could function by utilizing READ_VAR and WRITE_VAR function blocks over your network (Modbus TCP or RS485 serial) and addressing the IO indirectly through %M and %MW with some programming. It could also involve accessing the IO points (%I, %Q, %IW, %QW?) in a similar manner. Please note that while Machine Expert Basic may serve your needs, upgrading to Machine Expert (a Schneider Codesys system) may not seamlessly translate any solutions you develop here. Consider opting for the Ethernet models whenever available.
Hey there, your plan for distributed IO with the M221 PLCs sounds like a solid starting point. I've worked on a similar system before, and I have to say Modbus protocol really cuts down on the cabling requirements and makes the system more efficient. Keep in mind that communication between PLCs over Modbus can sometimes get tricky especially if it involves critical real-time decisions. Data latency and reliability should be seriously considered. Also, ensure you have a robust network infrastructure for the plant room to handle possible communication issues. And for redundancy, I advise having some hardwired safety interlocks. To simplify your work, make use of the peer cop function in the M221 for most of your module-to-module communications. Good luck with your proposal!
Great approach there, your focus on reducing cabling with distributed IO is quite thoughtful and efficient. I've worked on a similar system in the past. I'd suggest starting with ensuring that all your equipment is compatible with the MODBUS protocol as this is crucial for seamless communication. Do ample testing before the final implementation to ensure that the PLCs in the field are correctly reading signals and initiating the appropriate tasks. Don't forget to consider the external environmental conditions that might affect the transmission. Also, you'll want to ensure that you have a robust error-checking and handling mechanism in place to mitigate any communication failures. Hope this helps, and good luck with your project!
Sounds like an efficient plan to use distributed I/O approach with MODBUS protocol. It not only saves you from extensive wiring, but also optimizes the communication speed. I've worked with similar systems but on a smaller scale and M221 PLCs have always proven reliable. For your setup, I would suggest considering the use of shielded twisted pair cables to reduce any signal noise given the long distance to the farthest module. Also, you might want to look into fail-safe mechanisms for each module in the case of communication loss with the central PLC. Lastly, when programming the PLCs, keep a consistent and clear structure to make troubleshooting easier. Good luck with your project!
Your approach with using the M221 PLCs communicating via MODBUS sounds very efficient. I worked on a similar project where we also decided to use distributed I/O with PLCs to minimize cabling. It acutely saved us a lot of installation time and costs. An essential thing to consider is ensuring that your network's communication is reliable and interruption-free due to the vast distances between each module. Ensure that the system redundancy is achievable to counteract any failures. I also suggest that simulation and testing are done thoroughly to make sure every module communicates as intended. Lastly, always carry out regular preventive maintenance; it can prevent very costly and inconvenient system downtimes. Good luck with your project!
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Answer: Answer: The proposed control system consists of 8 modules in the field and 1 plant room. Each module has 2 operating modes: Extract Only and Extraction & Rinse.
Answer: Answer: In the Extract Only mode, pressing the button closes a VFC in the main panel, activates a standalone pump set, and opens the module extraction valve for a set time period when the vacuum reaches the necessary level.
Answer: Answer: In the Extraction & Rinse mode, pressing the button follows the Extract Only process but also opens a separate rinse valve in the module for back flushing the tank before another extraction cycle.
Answer: Answer: The proposal includes using 1 M221 PLC in the plant room that communicates with the 8 M221's in the field via the MODBUS protocol as distributed IO.
Answer: Answer: Using the M221 PLC setup eliminates the need for extensive cabling to each module and a main control panel with numerous terminals and expansion modules, providing a more streamlined solution.
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