1794-AENT and BooTP Module Fault

Hi all,
I've been working on a few Flex IO modules lately. I am setting up a second one with an IP. Here's what I've been experiencing:

1. Connect to device directly and launch BooTP.
2. Can find device via MAC and set IP.
3. Configure IP of device successfully. In this case 192.168.250.3.
4. As soon as I configure the device the module faults. Blinking module status light in RED.
5. In Linx it shows a comm error of 01E0024. It shows as unrecognized device and an X through it.
6. However I can still ping the device! (so odd). I can browse to the web gui of the device.
7. The device also has 1794-IB10x086 and 1794-IE4X0E2 connected to it. I thought it was a device fault there so I disconnected those and just have the AENT.

I tried resetting the device and tried again and same error. Any thoughts?

Thanks in advance.

Welcome to the PLCTalk forum community !

Your description is consistent with their being another device on the network with the IP address 192.168.250.3, but that does not support EtherNet/IP and therefore can be detected by PING but not by RSLinx.

Before setting the FLEX adapter to that address, do a thorough job with Angry IP Scanner or ordinary PING or TCPing or a web browser to be sure there's nothing with that address on the network.

EtherNet/IP devices always accept a TCP connection on TCP Port 44818. That makes Angry IP Scanner and TCPing good ways to detect them, independent of any vendor-specific tool or utility.

On second thought... the flashing red Network LED indicates this is a connection timeout, not a duplicate IP (that would be solid red).

Are you 100% sure you are connected to the specific 1794-AENT you just configured, when you connect via the web GUI ?

Be very specific and careful with MAC IDs when you're setting up automation devices especially when you have several of the same kind.

Also: double-check to be sure your Network Settings in the DHCP/BOOP tool are correct so that the IP address, subnet mask, and default gateway are all compatible.

If this module previously was connected and configured to another PLC on this same network, try isolating the FLEX adapter from the network so it doesn't inadvertently get connected to by more than one PLC.

Thanks for getting back to me.

I forgot to mention the whole time I was troubleshooting I was connected directly to the device. Once I changed the IP I changed mine to match the subnet and then when I try to browse I can't see it and the device faults. i even tried another different set of IPs and the same result. it is a bit baffling...

Thanks for that clarification; it definitely narrows down the possible problems !

Doublecheck and triplecheck the "Network Settings" in the BOOTP/DHCP tool.

You need to have a Default Gateway that's on the same subnet as the IP address. Example:


0x0204 is an ordinary "connection broken" code in Rockwell-speak.

The ordinary process should be "Connect device, fire up BOOTP/DHCP server utility, make association, watch it assign new address, cycle power to device".

Most A-B devices can apply the whole TCP/IP configuration at once when you make a change without needing a power cycle, but doing a cold reboot after reconfiguring remains a powerful superstition for me.

hmmm this seems to be making a lot more sense and explains why I can ping it but not connect to it..

So the network settings menu is that related to the NIC on my machine or the device it finds? when I Add Relation it doesn't show a DG just the IP I want to configure it to.

Thanks again I think with your help here I can get this tjing sorted!!!

When the BOOTP/DHCP Server utility configures a device, it sends it more than the IP address: it also sends values for the device to use for the subnet mask, default gateway, primary and secondary DNS servers, and domain name (for DNS).

You can leave DNS settings empty, and you can leave default gateway empty. You only absolutely have to set the IP and Subnet Mask.

But if you do enter a Default Gateway address, it *must* be valid for the combination of IP+Subnet Mask that you're sending to the device.

The most common mistake is to leave Default Gateway set for 192.168.1.1 when you're actually setting up your devices for 192.168.x.y (where x is not 1).

Those values do not have to match the computer that is running the BOOTP/DHCP utility.

I feel like such a fool. I was wondering why I didn't see the prompt for the DG or SM. I should have looked around more!!!

Thank you so much. I will give this a try Monday morning and see how it goes!!

update: worked like a charm. thank you! what got me was that the IP under network setting was my device but the mask and gateway were for the target. I wish all the info was under the add relation

Thanks again Ken.

I'm glad it worked, and thank you very much for taking the time to post that update !