BMENOC0321 Card interfering with BMENUA0100 Backplane IP assignment

[Lawrence.Luu]

Hi SE Forums! Hoping to get some assistance in understanding why a BMENOC0321 card is causing a "Duplicate IP on backplane" issue for a BMENUA0100 card. 

Whenever we try to make an offline build and download to a PLC (Let's say in this case we have PLC A and PLC B and we are downloading to PLC A), PLC A's BMENUA0100 card will have its "RUN", "ERR", "SEC" lights flashing while it's "BS" light solid red and we will lose communication to the database. When debugging why this issue has occurred, we discovered that if we disconnect PLC B's BMENOC0321 card from the switch, PLC A's BMENUA0100 will return to normal. Hence the subject title.

PLC A and B are both on the same IP address and subnet range while the NUA card is on a separate IP and subnet ranges each. Both PLCs have their NOC Backplanes enabled. 

In terms of set up, we currently have two identical PLCs. The BMENOC0321 and BMENUA0100 cards each have a single connection to a switch which talks to a database. Currently we have communications between the PLC to database and database to our SCADA network. See below for cards which are used: 

- BMEH586040S

- BMEP58CPROS3

- BMENUA0100

- BMENOC0321

Are there any settings on the BMENOC0321/BMENUA0100 card we need to take a look at? 

Please provide any assistance if possible or let me know if you require any additional information. Ideally, we would like to see after an offline build and download the PLC will not require resetting the BMENUA0100 card. 

Thank you in advance!

 

[ciupol]

When you refer to PLC A and PLC B does it mean you run hot standby system?

Also please provide screenshots of IP configurations of CPU/NUA/NOC. Also screenshot from Tools->Ethernet network manager may be helpful.

[Lawrence.Luu]

Hi Ciupol, 

Turns out we have found the solution to the above. 

The DHCP server had to have a unique Device name compared to other PLCs. This is so it can be unique.