cj1g no longer can connect through ethernet

[kcor 1]

have a plant in dominican republic that has a omron cj1g plc controlling a waste water plant. Have been able to go online through our company network with no problems. Now for some reason that I confused about, i can ping the ip, but can not connect with cx programmer. I have attached some screen shots, any ideas would be apprecitated. There is not one person in the plant that has the omron software. Could it have something to do with the port 9600, have read somewhere where some firewalls will not allow connections. As far as I know, nothing has changed in the plant and IT confirmed that the ip has not changed. Confused, have tried all afternoon thanks, Document1.pdf

[René Heijma 1]

Could be anything. What is your own IP-address and how do you get on the network of the wastewater plant. Are you sure the PLC is answering your ping. Could be that some-else assigned the IP-address to another device and now you have a duplicate IP-address conflict, sort of. The subnetmask is class B. This means that there are a lot of devices. Not easy to distinguish the device. Are you using VPN's? IT can say that the firewall will pass port 9600 but are you really sure? Everybody is keen on security nowadays. Maybe they still blocked it off but on another place down the line. Just my two cents.

[Tech Fred 3]

Here are some things to look for. Make sure you subnet addresses have not changed. You can ping anthing but to connect to it you have to have a valid subnet or a valid gateway into its subnet. Check you firewalls. Some Microsoft security updates witll automatically block ports when installed. The same goes for any smart switches or routers especialy if firmware changes have been made. You may have to run wireshark or some other network sniffer to make sure the packets are going to the PLC and that responses are coming back. Lastly you might have to go to the plant and check for error codes on the PLC. Fred Loveless Senior Application Engineer Kepware Technologies http://www.kepware.com

[james_applied 0]

Are you using UDP or TCP port forwarding. I could not connect to one site till they changed from TCP to UDP.

[kcor 1]

Thanks for advice. I connect to the plc, or at least I was directly through our company network. I just plug my laptop into a switch on my desk that is connected our company network and go online with all of our equipment. Have contacted someone in our IT group to find out if the port 9600 is causing a problem, read somewhere where some firewalls may block that port after updating. Also have a co-worker who has cx on his pc, and he can ot connect either. He can ping it as well, or at least we are pinging something. According to IT in the plant in dominican republic that is the correct IP, they would have no way of changing it.

[kcor 1]

Was able to get my communication issue solved today. A omron rep named Mike Walsh was in today to demo his omron drives and showed him my problem. Was able to ping plc in dominican republic but not able to connect with my pc anymore. Found out a couple of things. For some reason cx programmer was using the last numbers of my wireless network connections. Disabled the wireless connnections and changed some setting in CX. I have attached a file with some screen shots with a explanation of what we changed at the end. Maybe it will help someone else. Was very impressed with Mike Walsh and his level of knowledge. wasteWaterConnections.pdf

[Jay Anthony 118]

Attaboy, Mike!

[PdL 71]

I can't stress this out enough folks check if your wired network adapter (the one which you most likely will use to connect and thus its number gets filled in the workstation ID field) is set as the primary adapter in Windows. If not, put it on top!! This will save you this very problem kcor ran into. Disabling the wireless adapter or unchecking Auto connect will do the same but is actually a workaround and this is the proper solution! This tip is so underestimated and overlooked so often!! Check the how to guide here!

[Michael Walsh 268]

I noticed something else when I was there. When we connected with the Ethernet communications option, the autodetect used the last octet of his wireless router card, but when we connected using Ethernet (FINS/TCP), it used the last octet of his wired connection. I just confirmed that it does the same thing on my laptop. I am not sure how it determines priority in that case. Also, kcor seems to use both his wired and his wireless connection, so changing his priority may reduce how often he needs to use the "work around" of manually entering his node number, but it will not resolve his issue completely. It is good to get into the habit of checking the node number when you configure your connection.

[René Heijma 1]

Good job, Mike. I must agree. You can check with the node number on which port (wired or wireless) the request is sent out. Then it depends on the IP-address and sub-net mask. If it is taken the right connection. You can force it to go to the correct port by entering the last octet of the IP-address of that port.