1794-AENT with unknown IP + PLC Tools SIM-IPE = success

[bob12]

I'm sure this question has been posted a thousand times on here but for me it was even funnier when I got to ask Rockwell / AB directly. My question to them, I have a 1794-AENT without the rotary switches, I don't know the IP, how do I reset it? The person I spoke to gave me a sad look and said we typically tell people to throw them away as there's no way to reset them.

And maybe there are ways and I've just never stumbled upon them. I've always thought about ARP or something with wireshark which I'm not very good at but just never found anything. Somehow through the youtube magic I recently watched one of Tim's videos and he walked around his lab or classroom with this SIM-IPE device and was basically sniffing all of the IPs. So I purchased one last week, got it today and plugged it directly into an AENT. And lo and behold it told me it's IP!!! It's amazing! Sorry I'm sure this is a waste of a post but I for one am just so happy to have a tool that works and will save us money. I know the newer AENTs have the rotary switches and the AENTRs do as well but you have no idea how many older AENTs without the rotary switches the plants I frequent have. I bet hundreds! This device is a huge win in my mind and will save us a lot of time and money. And that's without even playing with the BootP features yet.

 

[dmroeder]

They throw them away? Plug directly into it, fire up wireshark, eventually there will be a ARP request that the device sends out, revealing its IP address..

Everyone that buys that IP Explorer seems to love it.

 

[AlfredoQuintero]

Install RSLinx. The RSLinx sends peridically ListIdentity boradcasts and you can find the IP address and change it.
Unless the IP settings is configured through DHCP or BootP in which case you will need a DHCP server or BootP server. The RSLinx suite includes such utility. You can download it for free from Rockwell Automation's site.
Of course, dmroeder solution is much faster to find out the IP address.

 

[bob12]

So question for both of you, dmroeder, I will install wireshark and give that a go. What IP does my laptop need? Do I leave it at DHCP? Guess I don't fully understand how if my laptop has a 192.168.1.x IP and the AENT has a 10.x.x.x address (which I didn't know it had that address) how wireshark would see it when it should only be looking at the 192.168.1.x range.

Alfredo same question for you. I have RSLinx installed and have pretty much used every driver in one way or another. With the two ethernet drivers, if my laptop is at 192.168.1.x and the AENT is at 10.0.0.0, and remember my situation is I have no idea what it's IP is, how would linx find it? Even if I swapped my situation, I'm 10.x.x.x and the AENT is at 192.168.1.x. On my laptop with a subnet of 255.0.0.0 wouldn't I still ignore anything that's not 10.x.x.x?

 

[plvlce]

So question for both of you, dmroeder, I will install wireshark and give that a go. What IP does my laptop need? Do I leave it at DHCP? Guess I don't fully understand how if my laptop has a 192.168.1.x IP and the AENT has a 10.x.x.x address (which I didn't know it had that address) how wireshark would see it when it should only be looking at the 192.168.1.x range.

ARP requests are a layer two broadcast; they are sent to all physically connected devices.

Your laptop will not process the ARP request, but it still receives it even though it doesn't do anything further and you can use wireshark to examine the received packet and pull the sender address.

 

[AlfredoQuintero]

So question for both of you, dmroeder, I will install wireshark and give that a go. What IP does my laptop need? Do I leave it at DHCP? Guess I don't fully understand how if my laptop has a 192.168.1.x IP and the AENT has a 10.x.x.x address (which I didn't know it had that address) how wireshark would see it when it should only be looking at the 192.168.1.x range.

Alfredo same question for you. I have RSLinx installed and have pretty much used every driver in one way or another. With the two ethernet drivers, if my laptop is at 192.168.1.x and the AENT is at 10.0.0.0, and remember my situation is I have no idea what it's IP is, how would linx find it? Even if I swapped my situation, I'm 10.x.x.x and the AENT is at 192.168.1.x. On my laptop with a subnet of 255.0.0.0 wouldn't I still ignore anything that's not 10.x.x.x?

Since Wireshark is a capture tool that only reads packet from the network, just to detect ARP or DHCP packets it does not matter which IP settings the lapptop has. Now, if you would like to change the IP settings of the Rockwell device, in that case the PC will need an IP setting compatible with the Rockwell device.