OPC instead of modbus
we are using modbus rtu for communicating between DCS (abb800xa) and ESD (HIMA) and since low speed transmission between these two we are going to use OPC instead. couple of question have raised for me. 1- does OPC is reliable and would speed improve? 2- does OPC would be installed on connectivity server or other servers (we have to control network and 2 * 2 connectivity server)? does it need to be reduanded and if so is it possible make redundant two opc? does OPC need license and how many? what are disadvantages of using OPC and problems that may occur? and finally and more importasntly does it affects system load compared to using modbus? system load would decrease or increase?
Asked 5 months ago
Voted best answer
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Hi!
As I understand it, you are opting to switch from Modbus RTU to Modbus Ethernet? (Otherwise I can't see major benefits)
The ABB 800xA system supports redundant Connectivity, like PLCConnect (?) for supporting the object-oriented model, which is a fundamental part of the system.
To answer the question of redundancy is possible to use? I would say it is up to the OPC vendor and the ESD (HIMA) system.
From the licensing point of view you need to license your 800xA with new connectivity (PLCConnect) if you don't have it, or if you have just a couple of signals use generic OPC (no license). I would strongly recommend the first alternative.
Of course you need a third-party license for the OPC-server (Modbus Ethernet) like the Kepware EX.
Depending on the size of the system, network design and your version of 800xA, you need to set up a new pair of connectivity servers or deploy the new connectivity to a existing pair.
OPC is simple, fast and effective regarding for operator presentation and information, alarm & event, trending etc. If it comes to the real-time demands of control and interlocking, I would prefer a more deterministic approach (controller to controller/PLC).
BR
As I understand it, you are opting to switch from Modbus RTU to Modbus Ethernet? (Otherwise I can't see major benefits)
The ABB 800xA system supports redundant Connectivity, like PLCConnect (?) for supporting the object-oriented model, which is a fundamental part of the system.
To answer the question of redundancy is possible to use? I would say it is up to the OPC vendor and the ESD (HIMA) system.
From the licensing point of view you need to license your 800xA with new connectivity (PLCConnect) if you don't have it, or if you have just a couple of signals use generic OPC (no license). I would strongly recommend the first alternative.
Of course you need a third-party license for the OPC-server (Modbus Ethernet) like the Kepware EX.
Depending on the size of the system, network design and your version of 800xA, you need to set up a new pair of connectivity servers or deploy the new connectivity to a existing pair.
OPC is simple, fast and effective regarding for operator presentation and information, alarm & event, trending etc. If it comes to the real-time demands of control and interlocking, I would prefer a more deterministic approach (controller to controller/PLC).
BR
Answered 5 months ago
Answers
1
THough you can use OPC for to Connect DCS ESD, it is not recommended if you are using to send commands.
For data monitoring and display it is fine.
You might also need to use an OPC bridge, which increases the overhead.OPC performance is limited by its various data sources, opc bridge itself can hande around 10000 data points.
For data monitoring and display it is fine.
You might also need to use an OPC bridge, which increases the overhead.OPC performance is limited by its various data sources, opc bridge itself can hande around 10000 data points.
Answered 5 months ago
0
I would look into a profibus connection between a controller on the ABB system and a controller from Hima.
0
> "communication between DCS and ESD is bidirectional it means both ESD and DCS writes to eachother. what happens if it is like this?"
Following from this comment... You have not explained if this link is for the HMI or for transferring signals between Controllers ?
For the HMI - An OPC Connection is OK. See previous answers for how to make this work.
For transferring signals between the controllers, eg permissives, process data for control, interlocks etc. then OPC is **NOT** recommended
Following from this comment... You have not explained if this link is for the HMI or for transferring signals between Controllers ?
For the HMI - An OPC Connection is OK. See previous answers for how to make this work.
For transferring signals between the controllers, eg permissives, process data for control, interlocks etc. then OPC is **NOT** recommended
Answered 5 months ago
0
. Doublepost
Answered 5 months ago
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