Two VIM2 cards as masters on a single IP Segment, Is it possible/proven?

We have an existing MODBUS TCPIP segment with a number of Slave MODBUS TCPIP devices on that segment. We have one VIM2 card connected below an existing DeltaV controller acting as a master device communicating with those existing slave nodes. All is well and working.

We have a VIMNET programming workstation connected to that segment.  See the image below for the current arrangement shown as items outlined in blue.

 

We are adding a further DeltaV controller to the system and wish to add further MODBUS TCPIP devices to communicate directly with that new controller through a new VIM2 card, see items outlined in orange.

We DO NOT require the existing VIM2 node to communicate with the new slave devices, and we DO NOT require the new VIM2 node to communicate with the existing slave devices. The existing and new MASTER/SLAVE relationships are logically separate and will remain that way.

We would like to retain a common physical TCPIP segment and address range, allowing us to retain our existing single programming workstation and VIMNET explorer.  The diagram shows our proposed and desired arrangement.

My understanding is that the MODBUS TCPIP protocol does allow multiple masters on an IP segment (unlike traditional MODBUS RTU)

So the questions are.

1. Does the VIM2 with the  IOD-4111 - MODBUS TCP IP DRIVER FOR DELTAV VIM2 support this arrangement?

2. Does anybody have experience of using this arrangement?,

3. Are there any concerns / tips / contraints?

 

The alternative would be to have a totally new separate physical IP segment and switch and a second VIMNET programming workstation. 

Many thanks,

IntuitiveNeil

• 8 Jul 2020 7:30 AM
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7 Replies

• Jake Nichelson

  

  • 8 Jul 2020 12:39 PM

  Neil,
  
  What you are proposing here will work and is a common solution. The Modbus TCP/IP protocol allows for multiple clients (masters) on a network - there is no limit. You can have multiple VIM2s, EIOCs, and PK controllers on the same network all acting as Modbus TCP/IP clients.

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• IntuitiveNeil

  

  • 8 Jul 2020 12:51 PM

  In reply to Jake Nichelson:

  Thanks Jake,
  
  I understood MODBUS TCPIP allowed it, just wanted to know there were any limitations with the VIM2 implementation that prevented it, such as fixed IP address (for itself) or anything odd like that.
  
  
  Regards

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• Lun.Raznik

  

  • 8 Jul 2020 9:23 PM

  In reply to IntuitiveNeil:

  Just to add - Modbus TCP/IP is point to point protocol (request/receive) only. The slaves (servers) _generally_ don't care who is addressing the node.
  
  I say _generally_ as I have seen devices where you can configure who can talk to it. And ther are also transparent firewalls that that can do the same.

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• lazy_engineer

  

  • 8 Jul 2020 9:41 PM

  I have an IO network that includes 5 VIMs with a combo of ModbusTCP and EtherNet/IP drivers. Various Modbus devices, PLCs, skids, instruments, analytical equipment, etc. live on that network and are integrated to DeltaV with the VIMs. At some point in the network growth it made sense to set up VLANs for each group to eliminate unnecessary chatter and improve uptime.

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• IntuitiveNeil

  

  • 9 Jul 2020 7:22 AM

  In reply to lazy_engineer:

  Thanks, it sounds like our proposal is a runner then.

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• IntuitiveNeil

  

  • 9 Jul 2020 7:25 AM

  In reply to Lun.Raznik:

  Thanks, and I'm corrected on my terminology "clients" and "servers" now not the old RTU term "masters" and "slaves"
  
  A subtle change but I guess it brings me into to 2000's

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• Ahmed

  

  • 12 Jul 2020 5:29 AM

  
  Good morning 

  
  

  I have one controller in my plant which gives hardware alarm 

  
  

  Node not configured 
  
  Sent from Yahoo Mail for iPhone
  
  

  On Thursday, July 9, 2020, 1:05 AM, Lun.Raznik <[email protected]> wrote:

  Update from Emerson Exchange 365 Lun.Raznik Have you tried this link? emersonexchange365.com/.../ Try to disable all notificaitons. View online   You received this notification because you subscribed to the forum.  To unsubscribe from only this thread, go here. Flag this post as spam/abuse.

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