OPC specifications question

Hello everyone !
Would an application supporting OPC DA 3.0, support the OPC DA 2.05 specs too?

Thank you in advance !

Hello,

An interesting question. The OPC specification has required interfaces and optional interfaces.

To be one version or the other you must have the required interfaces to pass the conformance test for that version.

Someone could make a server that has all the V3 required interfaces and none of the V2.

Which leads to the answer, no. Has it been done or practical, that is a different question.

I could see someone making a new V3 complaint server and not implement the V2 interfaces.

My2c.

Thank you very much Mark!
A very clear answer

Honeywell's paperless recorder had an option for an OPC 3.0 DA A&E server built into the recorder.

No one ever got it to work with any OPC client that was considered OPC version 2. (I never understood where one could even determine the OPC version level on a conventional OPC server).

Honeywell's OPC 2.0 DA server that was part of their Windows application software package works OK with OPC 2 DA clients.

From that experience, I concluded that OPC is not backwards compatible.

danw said:

Honeywell's paperless recorder had an option for an OPC 3.0 DA A&E server built into the recorder.

No one ever got it to work with any OPC client that was considered OPC version 2. (I never understood where one could even determine the OPC version level on a conventional OPC server).

Honeywell's OPC 2.0 DA server that was part of their Windows application software package works OK with OPC 2 DA clients.

From that experience, I concluded that OPC is not backwards compatible.

Click to expand...

Thank you very much ! I appreciate it !

Hello,

>From that experience, I concluded that OPC is not backwards compatible.

Yeah or the other way to look at it is the V2 clients are not forward compatible, which is not uncommon in most software.

From the stated example, Honeywell did not include V2 interfaces, excluding all V2 clients.

That is unless you have a server that incorporates all the OPC standards...

• Application Connectivity: KEPServerEX has been enhanced to provide the widest range of connectivity of any server product available. KEPServerEX supports the following client server technologies:

OPC Data Access Version 1.0a
OPC Data Access Version 2.0
OPC Data Access Version 2.05a
OPC Data Access Version 3.0
OPC Alarm and Events AE version 1.10
OPC Unified Architecture (UA) Version 1.01
FastDDE for Wonderware
SuiteLink for Wonderware
DDE Format CF_Text
DDE Format AdvancedDDE
NIO Interface for iFIX

http://www.eternity-sales.com/Kepware/kepserverex.htm

Disclosure - ESI is an authorized Kepware Distributor.