Optimal I/O System Design for Expanding Operations: Enhancing Control with CompactLogix and ControlLogix Integration

Question:

We are planning to expand our operations by adding a 16-tank farm that will feature a Clean-In-Place (CIP) system along with a valve matrix containing approximately 80 valves. Our current tank setup does not employ a matrix, resulting in a relatively low Input/Output (I/O) count, which is managed using several POINT I/O racks, each housing around 20 modules configured in a ring topology. Control is maintained through a 1769-L33ER CompactLogix processor. The new matrix will necessitate 480 Digital Inputs (DI) and 240 Digital Outputs (DO), with each valve requiring 3 outputs for actuation and 6 feedback signals. Since POINT I/O modules are limited to a maximum of 8 points, a solution with higher I/O density—ideally 32 points—is required. I do have several questions regarding this project. First, we need a controller equipped with more than 4MB of program memory, as we are nearing the limit of our current 2MB capacity. While the latest CompactLogix controllers feature this expanded memory, there appear to be compatibility concerns between POINT I/O and our existing 1769-L33ER CompactLogix controller, as referenced in this article: https://rockwellautomation.custhelp.com/app/answers/detail/a_id/772353. Therefore, I believe remaining with an older line may be more prudent. The older 1769 CompactLogix models only offer a maximum of 3MB of memory, which is inadequate for our needs. Instead, I am considering utilizing our available 1756-L73 ControlLogix system. I plan to connect the matrix to local I/O; however, the largest chassis accommodates only 17 slots, which is insufficient for the total I/O needed for the matrix. I'm curious whether a ControlLogix system can directly control a remote CompactLogix rack. Am I mistaken in thinking that I could connect multiple CompactLogix modules to an adapter to function similarly to a higher-density POINT I/O rack? In summary, does this configuration make sense, and will it be compatible with my current setup? To clarify, this system will be integrated with the existing ring network, consisting of: - **ControlLogix 1756-L73** with a dual-port Ethernet adapter housed in a compact chassis with no local I/O. - **CompactLogix I/O rack** featuring a 1769-AENTR module and approximately 24 modules allocated for the valve matrix. - **POINT I/O rack** employing a 1734-AENTR for the tanks and the CIP system. Thank you for your assistance.

Top Replies

When it comes to optimizing your valve matrix, consider the advantages of using AS-Interface technology to streamline your operations. By implementing two AS-I masters, you can efficiently manage up to 63 valves each, leveraging the benefits of this reliable 2-wire control network. Keep in mind that your valves will require AS-I modules installed in their heads for seamless integration. While I generally avoid using analog components on AS-I networks due to previous performance challenges, you may find that monitoring a tank farm could be feasible with analog integration in this case. For more information, visit [IFM](http://www.ifm.com/ifmus/web/pmain050_010_010.htm).

For those with greater expertise, your insights are valuable, but I recommend reaching out to your local representative. Request that they bring in a PLC (Programmable Logic Controller) specialist to assess your setup and engage in a discussion about the input/output (I/O) configuration. This collaboration can help clarify the project scope and identify potential solutions. Best, James.

Thank you for your responses! The suggestion regarding AS-I seems to be exactly what I'm looking for. Although I have no previous experience with it, we do utilize AS-I technology in several of our conveyor systems, so I need to get acquainted with its functionalities. The current matrix we have is sourced from a dairy processing facility. It features a large 1.5-inch trunk cable that branches out to each valve via a 4-pin connector. I'm uncertain about the specific I/O system in use. The connectors and cables are in poor condition, so I plan to replace them. Do you have any insights on whether this setup can be integrated into an AS-I network?

The connector in question is a standard M12 type and is not limited to a specific networking protocol. It's possible that it could be DeviceNet; do you notice a thick gray cable or any markings indicating "DeviceNet"? It might simply be standard I/O wiring. Examine the tops of the valve controls—if they have been previously utilized, your options might be restricted to what is already in place, unless you're considering replacing the control modules, if that’s feasible. If the valve contains an AS-I/DeviceNet control module, it should be clearly identifiable. AS-I cables are relatively straightforward to recognize; they typically come in yellow with a keyed design. For more detailed information, please refer to the link I shared earlier.

I may be approaching this topic incorrectly, so please feel free to provide clarification if I'm veering off track. I've been reviewing the link you shared, but I might be misinterpreting the information. To integrate an AS-I master into my ControlLogix chassis, I believe I would require the U71005 model, as it supports dual masters (see the details here: http://www.ifm.com/ifmus/web/asi-BplaneMasters.htm). The yellow keyed cable would facilitate both power and communication to the field modules. Are you suggesting that each valve must be equipped with specific AS-I control modules, in addition to the field modules? Something like this? https://www.alfalaval.us/products/fluid-handling/automation/control-unit/thinktop/. I re-examined the matrix and noticed that the cabling lacks branding. The control module appears to be poorly labeled, yet it does feature LED indicators for A and B, indicating AS-I addressing with an A/B selector, correct? I've included some images of the module for your reference. Each assembly consists of three modules—one positioned at the top, one at the bottom, and one at the drain. My aim is to establish the matrix within a standalone AS-I network that is compatible with our Ethernet/IP system, while ensuring that the tanks and CIP setups utilize POINT I/O to maintain consistency across our facility (so we will be using just digital I/O for the AS-I). Thank you for sharing your expertise on this matter!

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