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10/31/2016
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Hello, we have a SCADA system with over 500 Field Devices that communicate over Serial RS-232 at 9600 and 1200 Baud. The Protocols that we are using is MODBUS Binary and a Proprietary ASCII Protocol. We are changing out our SCADA System and won't be able to upgrade any field devices for a few years. Should we be trying to change over to an OPC-UA Communication Protocol or should we just have the new system support Modbus and the ASCII Protocol and upgrade to OPC-UA later? Thanks.
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04/15/2014
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If you do a google search for "OPC UA Modbus Serial" you will find many commercial OPC UA gateway servers that support the very popular MODBUS protocol. Since OPC UA is the most secure automation protocol available, I suggest you engineer your new SCADA system to use UA wherever possible. As you later upgrade your field devices and RTUs you should be able to have them communicate via UA natively and thus eliminate the older, insecure protocols entirely without major change to your new SCADA system.
10/31/2016
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Thank you for the info. I'm starting to understand OPC-UA and its positive attributes.
10/31/2016
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Hello, can I ask another question. Are there any current PLCs out there that can communicate natively using OPC UA? I can't seem to find any. I'm told that I would have to use a UA Server between the SCADA System and the devices.
Thanks.
There are several PLCs with direct OPC UA support already on the market.
A few of the vendors are Beckhoff, B&R and Siemens but I am sure there are more. You could visit the OPC Booth at one of the major industrial fairs (Hannover Fair or SPS/IPC/DRIVES in Nuremberg) to get more information.
10/31/2016
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Thanks for the information.
Is it true that in order to communicate OPC-UA Host to a field PLC using native OPC-UA the communications have to travel over high speed Ethernet? There's no way to use OPC-UA as the only protocol over Serial at 9600 Baud?
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