M580 Ethernet Comms with SCADA on different Subnet

[JohnnyHolland]

Hi, I am using an M580 PLC system with a BMEP581020 processor and we are unable to communicate via ethernet with it from the upstream SCADA system. The BMEP581020 Ethernet port is connected to a local managed switch which is on the same Subnet range and I can ping the PLC from this switch. However when I try to ping the PLC from the SCADA which is on a different Subnet range the ping does not work. I have another PLC with the same configuration on this site which is on the same Subnet as the SCADA and I can ping this PLC from the SCADA. Is there any restriction on communicating with M580 PLC's from a different Subnet? Or can you advise on how I may resolve this issue?

[RoozeeR]

Hello Sean,

When communicating with a device (M580 or others) which are located on a different subnet, there has to be a Router device in between. This Router will connect both subnets and route the messages from subnet to subnet. In both device (SCADA and M580) a gateway need to be configured where the gateway is the IP address of the Router, connected to the device.

If this is not clear, please share a picture with network configuration and IP/Subnet/Gateway settings.

[JohnnyHolland]

Hi R.Roozee,

Thank you for the reply, I should have mentioned that there is a router and the Network IT specialist assures me the routing is correct (I have my doubts). If the routing is correct are there any limitations with the M580 CPU ethernet ports that would stop the PLC responding to correctly routed messages from the SCADA?

Thanks. 

[RoozeeR]

Hello Sean,

Most common issue, are the security settings. By default Access Control is enabled, with access for only it's own subnet (not for your SCADA). Also you have to enable port 502. You can add the IP address of your SCADA to the access control list and enable port 502, or press Unlock Security.

For security reasons it's always a good idea to think about who can do what, so add security to the level needed.