How to Monitor Ethernet Node Status in RSLogix: Step-by-Step Guide

Question:

Looking for an efficient method to check the connection status of different ethernet nodes in RSlogix? I have a small automation setup with cameras and barcode readers that communicate directly with my robot, not listed in the RSLogix hardware tree. I want to monitor their communication status on the HMI. In the past, I used a Hirshmann ethernet switch to read port status, but with a Cisco IE-2000 switch in use now, I can't find instructions on how to do so. Is there a way to utilize the MSG instruction to send a basic "Are you alive" message to an IP address and receive a pass/fail response? The processor is a 1769-L33ER running software version 30.11.

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In order to determine if the devices are EtherNet/IP compatible, I have utilized the MSG command to execute a CIP Generic message for reading Class 1, Instance 1, Attribute 1 (Vendor ID). As the Identity Object (Class 0x01) is a required component, EtherNet/IP devices will always provide a response. While there isn't a direct method for conducting an ICMP PING with ControlLogix, a potential approach could involve modifying the Generic Sockets code to establish a TCP connection with any open TCP ports on these devices, such as port 80 for a HTTP webpage or port 502 for Modbus/TCP functionality.

I am aware that my barcode scanners are compatible with Ethernet I/P, but I am unsure if the vision camera, being essentially a PC, also supports this feature. It is worth a try. Thank you!

Although this thread is old, it seems to relate to my current project. I am working on setting up a CIP generic message to check the online status of a Nematron HMI. I just need a basic status update. Despite receiving connection timeout errors, I am able to ping the device. Can anyone offer assistance with this issue?

Is it possible to incorporate the Human Machine Interface (HMI) into the Input/Output (IO) tree/configuration of the ControlLogix (CLX) system? With the GSV Module EntryStatus instruction, you have the capability to access and interact with any ethernet device listed in the IO tree.

Robertmee inquired about the possibility of integrating the Human Machine Interface (HMI) into the Input/Output (IO) tree and configuration of the ControlLogix (CLX). It is possible to communicate with any Ethernet device in the IO tree using the GSV Module EntryStatus instruction. However, attempts to connect the HMI as a generic device or through messages have been unsuccessful, leaving Robertmee puzzled by the issue.

Yes, that's absolutely possible! You can use MSG instruction to send a "ping" or "are you there" request. If you're not getting a reply, then the device is likely not connected. The steps would be to setup a MSG instruction to read an innocuous register in the remote device, if it fails, you know the device is disconnected or off. You can put these instructions into periodic tasks or use GSV/SSV instruction to achieve the same result. Do consider that this will add some overhead to your processor but should be minimal if you're only checking a handful of devices. An advantage of using MSG is that it gives you more control, for instance, you set your own timeouts etc. Hope this helps!

You could indeed use the MSG instruction method to ping nodes for a status response. To do this, you'd set up your MSG instruction to an IP address with a service type like "get attribute single". The CIP standard specifies that nodes must respond to this sort of request. If the node is offline or otherwise unreachable, the MSG instruction will time out, giving you the fail status you're looking for. Regarding monitoring this on your HMI, you could use a multi-state indicator tied to the .DN and .ER bits of your MSG instruction. I would also recommend digging a bit deeper into the Cisco switch's documentation; they usually have extensive monitoring capabilities.

Absolutely, utilizing the MSG instruction in RSLogicks is indeed a viable method to monitor the communication status. You use the "CIP Generic" message type, and the service type should be "Get Attribute Single" (Service Code 0Eh) for the instruction. The trick lies in establishing a "Class/Instance/Attribute" (CIA) path. For most devices, the Class would be 0x01 (backplane), the Instance would be the Ethernet module slot number, and the Attribute would be 0x02 (status). A successfully executed instruction would mean your device is alive while a failed instruction means the device is off or there's a network issue. This might seem quite technical, but the beauty is in its simplicity once set-up. You can monitor the results on your HMI. Please remember to test this setup thoroughly to ensure it works as you expect it to with your specific devices.

It's quite possible to send a ping type message in RSlogix using MSG instruction. You would set up a message instruction in your ladder logic to read a 'dummy tag' in the non-existent PLC. If the message times out, it proves that there is no Ethernet connectivity to that IP address. Here, you could use the .DN bit as a pass/fail indicator, or the .ER bit to give you an error status. The hitch is that you need to make sure the timeout and msg retry times are set adequately to prevent flooding the network with retries. More detailed instructions can be found on the Rockwell Automation Knowledgebase website. Or, you can use the free Ethernet/IP Capacity Tool offered by Rockwell. This tool can provide insight into your network and device conditions. It is quite handy for network troubleshooting as well.

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Frequently Asked Questions (FAQ)

FAQ: 1. How can I monitor the connection status of different Ethernet nodes in RSLogix when they are not listed in the hardware tree?

Answer: - One way to monitor the communication status of Ethernet nodes not listed in the hardware tree is by using the MSG instruction in RSLogix. This allows you to send a basic "Are you alive" message to an IP address and receive a pass/fail response.

FAQ: 2. Can I use the MSG instruction to check the connection status of devices connected to a Cisco IE-2000 switch in RSLogix?

Answer: - Yes, you can use the MSG instruction in RSLogix to monitor the connection status of devices connected to a Cisco IE-2000 switch. By sending a simple message to the IP address of the device, you can receive a response indicating whether the device is reachable.

FAQ: 3. What type of processor and software version is required to implement Ethernet node status monitoring in RSLogix?

Answer: - To implement Ethernet node status monitoring in RSLogix using the MSG instruction, you can use a processor like the 1769-L33ER running software version 30.11. This setup allows you to efficiently monitor the communication status of various Ethernet nodes in your automation setup.

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