Configuring a 1734-AENT Adaptor

Hi Guys,

I have been trying to configure a 1734-AENT adaptor using the Rockwell BootP Utility and have been unsucessfull. I have read the user manual for the adaptor(Publ.1734-UM011) and can see the adaptor in my request history panel. When i double click on it, type the IP address I want for the adaptor and click OK, the adaptor is added to the relation list but it doesnt appear on the IP Address column in the request history panel. This signifies that IP address is not being assigned. What am I doing wrong? Please refer attachement for a screenshot of the BootP Utility.

Are you using a switch or direct conect with ethernet x-over cable. I have never had much luck with BootP unless i conect direct to it via x-over cable. Also disable firewalls etc

First, your PC should have a static IP address before you start to use the BOOTP/DHCP Utility.

Second, you need to make sure that the Tool ->Network Settings in the BOOTP/DHCP Utility for the Subnet Mask and the Default Gateway are configured and are consistent with the IP addresses you are trying to assign with the Utility.

The DNS Servers and Domain Name settings can be set but are not required.

Sometimes firewalls and policies to interfere with this utility, though I've had very few problems with it. Running Wireshark on your local computer while executing the utility will give you insight into exactly where the sequence is failing.

Thanks for your reply guys. I have the adaptor connected via a switch to our production network. When my laptop is on DHCP, I can see the adaptor in the Request history panel but cannot assign the new IP address. On the status bar it indicates that it is "Unable to service request from MAC of the adaptor". I tried giving my laptop a static IP but it didnt work. With the static IP I cant even see the adaptor in the request history panel. Maybe I'm not setting the static IP correctly. Below are the IP and subnet for our production network which is connected to our office router.

Production IP Addresses: 10.10.16.xx
Subnet: 255.255.255.0
Gateway: 10.10.8.1

At first I connected directly to the adaptor with a static IP but showed nothing so connected it through a switch but still it wouldnt work.

Can anyone tell me what exactly do i need to put in my staic IP settings to get my laptop to talk to the adaptor? Is there any other simpler way to configure this adaptor?

Thanks in advance.

The BOOTP/DHCP Utility will not allow you to configure a device that cannot communicate with the Default Gateway address.

If the Subnet Mask is correct, then the 10.10.16.x network and the 10.10.8.x network are different subnets.

Could the Subnet Mask be 255.255.224.0 ? That would make the 10.10.16.x addresses and 10.10.8.x address both part of the same network.

Our current subnet for the office network is 255.255.254.0 and for the production network it's 255.255.255.0. I'm not sure why our IT guys did it that way but to change the subnet from the current to what you suggest may take quite long (you know the IT guys). Would that make a difference if I connect directly to the adaptor?

Take your laptop to the 1734-AENT.
Plug your laptop into the 1734-AENT via a ethernet x over cable. No switches, No gateways, No complication, No IT interference!
Set your Laptop IP address to something in the same range as what you want 1734-AENT to be
e.g (example only) 1734-AENT required address = 192.167.0.98
Laptop = 192.167.0.99. Subnet mask for both 255.255.255.0
Open BootP
Wait for MacID to pop up in request history box.
If it doesnt show up, cycle power to 1734-AENT
If it still doesnt show up, ensure thumbwheel settings on 1734-AENT are 999 and cycle power
Select Add to relation list
Message will say something like xxx.xxx.xxx.xxx address sent to mac id xxxxx
wait a few seconds
Select Disable BootP/DHCP
Message should say something like. BootP disabled.
Its been a while so a bit hazy on details.
Check you can see adapter on new address in RSLinx.
Cycle power to unit. Re-confirm IP address has been retained.
In RSLinx right click on adapter and set up port configuration with gateway address etc that your factory network requires. You can modify subnet here aswell.

Usually the DHCP/BOOTP Utility is very easy and straightforward. Your posts have me scratching my head and wondering if I understand IP addressing at all.

I do have to amend my earlier statement about the BOOTP/DHCP Server not being able to fulfill requests when the Default Gateway and the IP Address are on different subnets. I proved that it will do so by sending a 1756-ENBT on my network an IP address of 10.10.16.50 when the Utility configuration for the subnet mask as 255.255.255.0 and the default gateway as 192.168.1.1. Neither of those addresses are actually on my network.

The 1756-ENBT might be a little more forgiving than the 1734-AENT, though, in terms of accepting an IP Address and Default Gateway on different networks.

I'm not a low-level Ethernet or TCP/IP expert, but one thing I noticed is that the BOOTP/DHCP Utility gave a "unable to service request" for the first request from the 1756-ENBT, but correctly serviced the second one five seconds later.

In Wireshark, the first request is described by the decoder as "DHCP Discover" and the second is described as "DHCP Request".

I realize this should be easier to do, but I would strongly recommend getting to the bottom of it just by installing and running Wireshark.

The 1734-AENT is asking via DHCP not BOOTP.

Use the enable DHCP button in the "Relation List" area of the BOOTP/DHCP server to enable replies to DHCP requests.

I dont know why Rockwell went for DHCP instead of BOOTP for this device, everythinp else pretty much seems to be BOOTP out of the box.

Clash of the DHCP Servers !

:facepalm:

Short Answer: the corporate Router is giving the 1734-AENT an address before the BOOTP/DHCP Utility gets a chance to do so.

Long Answer:

The BOOTP/DHCP History that Viks posted looked like this:

15:38:06 DHCP 00:27:13:66:BE:BF
15:37:48 DHCP 00:00:BC:64:71:50
15:37:48 DHCP 00:00:BC:64:71:50

The top MAC ID is from a Taiwanese PC motherboard. The bottom two are from an Allen-Bradley 1734-AENT.

But there are only two. Viks might have grabbed that screenshot really promptly, but if he left the Utility running and the 1734-AENT didn't get an address from the Rockwell BOOTP/DHCP Utility, it should have kept on sending requests.

The DHCP request repeats itself with an exponential backoff that retries after 4 seconds, then 8 seconds, then 16 seconds, then 64 seconds, then 128 seconds (approximately).

I set up a test in my lab, which has an ordinary Linksys WRT54G router serving as a DHCP Server. I have a 1756-ENBT in a ControlLogix chassis, which should behave in a very similar way to the 1734-AENT.

With both the BOOTP/DHCP Server Utility and the Router running and configured, the BOOTP/DHCP Server Utility provides a configuration to the 1756-ENBT after two request packets appear in the History.

With the BOOTP/DHCP Server Utility unconfigured, and the router running, two packets appear in the History and then stop. When I check the 1756-ENBT I see that it's received an IP address from the Linksys router.

With the BOOTP/DHCP Server Utility unconfigured and the router unplugged, DHCP Discover packets continue to appear, indefinitely (I'm up to 64 of them while I've been typing this post).

When DHCP Servers compete, devices get their address from whichever one is quicker on the trigger. In my case, the Rockwell utility seems to win. In Viks case, I think the corporate router won.

There are two easy solutions to this problem:

1. Exclude the 1734-AENT from the DHCP Server configuration on the corporate Router.
2. Let the corportate router give the 1734-AENT an address, then scan for it using RSLinx Classic or a third-party scanner like Angry IP Scanner, FING, Netscan, or NMAP. Then use RSLinx Classic to reconfigure the POINT adapter.

One last thing, and then I'll stop.

The three "Enable/Disable" buttons don't configure the BOOTP/DHCP Server Utility, but rather send a configuration message to the device that's highlighted in the Relation List.

I always thought these were some kind of special DHCP message but I captured them this morning in Wireshark and saw that they are native ControlLogix CIP messages to the TCP/IP Configuration Object that set the BOOTP/DHCP Configuration options.

Those buttons function exactly the same as if you used the RSLinx Classic configuration applet or the Configuration Tab for one of these module profiles in RSLogix 5000.

I have tried almost all of what has been suggested above but yet it still wont work. I even left the utility running for one whole day but didnt get more than two requests from the adaptor. Attached is the ZIP file with all I recieved. Isnt there any other way to set this up?

cheers,

Do you have an alternate DHCP or BootP server running on your laptop that you don't know about? As Ken Roach said, some device somewhere is servicing the AENT DHCP/BootP requests. You said you tried everything listed, which I assume also means you tried the direct connection between the AENT and your laptop with a crossover cable. If you did this and the AENT still stopped asking for DHCP/BootP service after two requests the only logical assumption we can make is that another DHCP/BootP server on your laptop executed the service before you could with the Rockwell server.

Keith

Why not to set private IP with thumb-wheel switch first and use webpage or RSlinx to set it to something else after that. THis is the only module the allows you to do this

Contr_Conn said:

Why not to set private IP with thumb-wheel switch first and use webpage or RSlinx to set it to something else after that. THis is the only module the allows you to do this

Click to expand...

I agree!!! Doing this is soooo much easier than the BootP mess. The 1734-AENT manual shows how to do it. Fast and Simple!!