1794 AENT

[bryan372002 0]

Need to replace a 1794-aent and have only configured 1 and cant really remember how it was done. can i just install the new one and set the IP address thru control logix 5000 and then disable the boot/dhcp so the IP stays the same after reboot? tried to do it today with just boot/dhcp software and a crossover cable (and patch cable) and was unsuccessful. wouldnt connect. going to AB.COM now to study...lol

[TimWilborne 108]

DISCLAIMER - Suggesting a product that I sell, but it fits the bill. While it probably won't be worth it for a one time component swap, you may want to look at PLC Tool's IP X-Press. http://plctools.com/index.php?option=com_c...12&Itemid=1 You can use it to read the IP Address of your existing Flex I/O module, set the IP Address of your new Flex I/O module, and disable the Bootp/DHCP.

[Mickey 71]

Maybe this will help Address_1.pdf

[Contr_Conn 4]

No, you must use a BOOTP server to assign IP address, you can't do it via RSlogix5000 if module does not have an address. See pub ENET-UM001 page 28 or use device TWControls recomended

[bryan372002 0]

Thanks guys, all though the IP xpress looks like a great tool I dont think i could justify the cost, no more than it would be used. we do have rockwells bootp/dhcp server software but i couldnt seem to get a connection.

[TimWilborne 108]

Turn off any firewalls or internet security softwares that could block ports

[Contr_Conn 4]

If you connect cable directly then it must be crossover cable, or use two straight cables and switch. If your computer has VPN software then disable it: post screenshot of you local area connection configuration - I will tell you what to disable.

[bryan372002 0]

Thanks, I dont have the laptop at home with me but will be back o it monday. I believe the last one we done, we actually put it in the rack and connected to it from the network that the Flex I/O resides on. what I was trying to do was connect to the aent with a crossover cable on the bench and configure the IP so when the time comes I can just pop it in the rack and go... I may get back with You guys monday if I cant figure it out. Thanks for the assistance.

[TimWilborne 108]

The crossover cable should have worked fine. Check the IP Address of your computer. It must be on the same group as the Flex I/O default (I'm thinking 192.168.1.XXX, but am too lazy to look it up right now)

[Contr_Conn 4]

This is incorrect statement: - AENT does not have a "default IP", it comes out of box with 0.0.0.0 - To use BOOTP server PC and AENT don't need to be on the same subnet, it is necessary only if you want to make IP address static after IP address assigned. Also AENT ser B has thumbwheel switch that allows quick setup if 192.168.1.xxx addressing used. For any other addressing scheme it needs to be set to 999 Edited 26 Jul 2008 by Contr_Conn

[TimWilborne 108]

Thanks for the correction, I guess it was a bad time to be lazy

[bryan372002 0]

treid again today with this bugger using a cross over cable with no luck what so ever. seems the laptop turns off the Lan card when it is on battery power may be one issue. I may try again with laptop power supply hooked up, but what I am thinking now si since we have done this before is to just put the 1794_Aent in place and online and hook laptop up to the network and run the BootP/dhcp server from there ? would this be a problem ?

[paulengr 44]

I haven't tried this (since I don't currently have an AENT module to experiment with), but if you have a standard Windows type BOOTP/DHCP server on the network that just issues "pool" addresses, and since the device will respond to Ethernet/IP packets (that's the point of the AENT module), then can't you just let it roam freely on the network and access it (and change the settings) via RS-Linx Ethernet/IP auto-directory? Once you have the IP address, then you could configure it from Logix5000 just long enough to set the correct IP address. By the way, this is what my question was about in the general forum...I've been thinking about the idea of assigning IP addresses based on the switch & port they are plugged into, which allows "autoconfig" since the addresses will always end up the same no matter what device is plugged into the port as long as it recognizes DHCP/BOOTP.

[Ken Roach 194]

The usual problem, Bryan, is that most PCs are set up to get their IP address from an office server using DHCP. The moment you unplug them from the office network, they dump that IP and wait to get plugged in again. If you then plug your PC with a crossover Ethernet cable into a 1794-AENT, the PC just sits there sending out DHCP requests. The 1794-AENT is probably sitting there sending out BOOTP or DHCP requests, too, but the PC can't service them because its Ethernet interface is still unconfigured. Thus the Belgian standoff. What I do is set up an "Alternate Configuration" in Windows for my hardwired Ethernet port. When I plug into a switch or crossover cable, my PC attempts to get an IP address via DHCP, then times out and sets itself to this Alternate Configuration (in my case it's 192.168.1.61). Then I can go online with 80% of the EtherNet/IP networks I work on. A advanced and useful approach to Ethernet devices that lack a non-Ethernet method to configure them: When you plug a 1794-AENT into a switch, one of the first things it does is send out a "Gratuitous ARP Request" to determine if there is a duplicate IP address on the network. If you plug into the switch with an Ethernet analyzer like Wireshark, you can see that broadcast appear immediately after you plug in the 1794-AENT. Now you know the module's IP address, whether you're on the same IP network or not.