Configure Ethernet Driver for PLCs on Different Subnet

whussain6 · Aug 18, 2015

Hi Guys,

I am trying to configure single Ethernet driver in RSLinx which can allow me to go online with two different PLCs on different subnets with IP addresses e.g. 10.11.187.xx and 10.11.188.xx without me changing my laptop IPV4 settings.

The subnets are connected through router. Does anybody know which drivers and what configuration do I need?

JeremyM · Aug 18, 2015

You can add another Ethernet driver with a set of pre-defined IP addresses in RSLinx. I've had trouble using the discovery provided by RSLinx, even while on the same subnet, so this has been my workaround.

MarkNightingale · Aug 18, 2015

Try changing your subnet mask to 255.255.254.000 or 255.255.248.000

Cheers

Mark

GaryS · Aug 18, 2015

Ethernet devices
then go to configuration enter the IP address of the devices you want to access
the IP address has to be in the list to be scanned but the list dos not have to be in the same subnet
all the devices you want to access has to be connected on powered up

whussain6 · Aug 18, 2015

JeremyM said:
You can add another Ethernet driver with a set of pre-defined IP addresses in RSLinx. I've had trouble using the discovery provided by RSLinx, even while on the same subnet, so this has been my workaround.

I have tried adding AB_ETH_1 driver with 10.11.187.xx and 10.11.188.xx predefined but I can only find 10.11.187 as my pc is on 10.11.187 as well.

MarkNightingale said:
Try changing your subnet mask to 255.255.254.000 or 255.255.248.000

I cannot change subnet mask as it is given by the IT guys and needs to 255.255.255.192 in this example prototype.

GaryS said:
Ethernet devices
then go to configuration enter the IP address of the devices you want to access
the IP address has to be in the list to be scanned but the list dos not have to be in the same subnet
all the devices you want to access has to be connected on powered up

I have used Ethernet devices and assigned IP address, but still I can ping 10.11.188 from my PC which is on 10.11.187 but RED cross in RSlogix

GaryS · Aug 18, 2015

check you firewall settings they can block addresses not on your local subnet
if you are getting the red cross then that address in not available but I in the scan list.

whussain6 · Aug 18, 2015

no, firewall is turned off

GaryS · Aug 18, 2015

check the router settings it may be blocking that subnet

diat150 · Aug 18, 2015

can you ping the plc on the remote network?

ASF · Aug 18, 2015

Forget what the IT guys told you for subnet, changing that won't hurt anything. Set it to 255.255.255.0.

You will need to make sure that both PLC's and your PC have the address of the router set in the gateway field. Note that the gateway address will be different for each subnet.

Then, as described above, make sure you're running the Ethernet Devices (not Ethernet/IP) driver, and manually add your two IP addresses.

If you still can't see one of the PLC's, try to ping it. Until you can ping it, it's never going to show up in RSLinx.

It can also be helpful to disable any other network adaptors while you troubleshoot (e.g. wifi). If you're using a VM there are things to be aware of in your virtual network adaptor setup as well.

OkiePC · Aug 18, 2015

ASF said:
Forget what the IT guys told you for subnet, changing that won't hurt anything. Set it to 255.255.255.0.

I think you meant 255.255.254.0 (since he has two different subnets but the first two octets are identical). I agree completely with the first half of your statement. You will not be able to access both of them simultaneously without changing the subnet, unless there is some sort of address translation being done for you by the "IT guys".

ASF · Aug 18, 2015

The first post mentioned that the subnets are connected through a router, so I figured just set it to 255.255.255.0 and let the router do it's job. Of course, the router can only do it's job if the PLCs and PC all have the gateway address set. If not, your subnet mask would have to be 255.255.248.0, as "187" is binary 10111011 and 188 is binary 1011100, so the tird octet of the mask would need to be 11111000, which is decimal 248

ASF · Aug 18, 2015

The subnet mask the IT guys have given him (255.255.255.192) will only let him see addresses 10.11.187.0 through 10.11.187.63. It won't even let him see the whole subnet he's on

robo77 · Aug 19, 2015

If just pc why not add second subnet to card?

whussain6 · Aug 19, 2015

GaryS said:
check the router settings it may be blocking that subnet

Thanks all for your valuable suggestions. It was router settings which was blocking the traffic between the two subnets.

Configure Ethernet Driver for PLCs on Different Subnet

whussain6

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