Change Subnet On CP1L PLC

[OmronOmicron]

I am trying to change the subnet of this CP1L plc. Currently it is at 192.168.250.*** and I would like to change it to 192.168.54.***. I already tried starting fresh by writing to the controller with ip 0.0.0.0 and then putting my desired ip address after. When I try to write to the controller with a subnet other than .250 for example 192.168.54.13, the controller saves the node address(.13) but keeps the same .250 subnet which results in me being able to ping 192.168.250.13 successfully but get no response from pinging 192.168.54.13. Yes I did change my local network card when pinging different subnets and also did a network reset in CX-P after every ip change.

Let me know if there is anything I am missing!! 

Edited August 23, 2022 by OmronOmicron
typo 169

[Michael Walsh]

Is this a CP1L (with an adapter) or CP1L-E with a built in port? It sounds like a CP1L-E, but I just want to make sure.

[OmronOmicron]

it's a CP1L-EM40DR-D

[photovoltaic]

Set the IP and subnet on the PLC

Set your PC on the same subnet

Cycle power on the PLC

[OmronOmicron]

Thank you for the replies! So I ended up finding the issue but not the remedy. So the fault light appears when the subnet mask is changed from 255.255.255.0 to 255.255.254.0.

I was able to change the ip address to a different subnet which answers my first question, but still no success with the subnet mask.

@photovoltaic if you would like to give that a try and let me know if you get the same results.

I am going to look in further detail why the eip card does not like changing to a different subnet mask.

I do need it on this mask in order to integrate it to the network.

Basically why I was getting faulty results from changing the subnet was because i was also changing the subnet mask. So when I left the subnet mask alone(255.255.255.0) I was able to change the ip subnet to whatever desired. 

Found on a manual:

Edited August 22, 2022 by OmronOmicron
add attachments

[photovoltaic]

No issues here:

 

[IO_Rack]

I'm Mr. Walsh will reply but in the meantime, I remember someone having issues when using a subnet outside of the typical 255.255.255.0 range. I don't know this is the same issue but see this post:

CJ2M Ethernet IP error F3 - Omron - Forums.MrPLC.com

 

[OmronOmicron]

@photovoltaic im sorry the ip addresses I gave were just examples, prior to me reading what @IO_Rack shared I didn't realize there was lot more to each value of an ip address. So the exact values I am using are 192.168.81.215 subnet mask 255.255.254.0

[Michael Walsh]

@IO_Rack shared a link that may help.  The controller should accept your settings and allow you to change the IP Address and Subnet to what you desire, however you may have issues connecting using FINS if you have something other than Auto (Dynamic) set for the FINS UDP conversion when you use a subnet of 255.255.254.0. 

 

[Michael Walsh]

I just tested this and am getting the same result as @OmronOmicron:

If I have this:

192.168.0.66

Subnet: 255.255.254.0

It works fine.

If I change it to:

192.168.1.66

Subnet 255.255.254.0

The PLC sets the IP Address to 192.168.250.66.

 

So, it is not just the fact that you are using a non class C Subnet, but rather that you are using the non Class C subnet and the FINS node calculation from the IP address / Subnet combo (see link in previous comment) creates a FINS node number that does not match the FINS Node number set in the PLC settings (below Subnet Mask).  This appears to be the design.