OPC on non-Windows platforms/ Alternative solutions

A

Thread Starter

Ariel Burbaickij

Hello forum participants,
Thread with exactly same topic was
handled in August 2001 so my message
can be considered as continuation and testimony of lasting interest in the issue. My questions
are:

1) Provided that DCOM is not real-time
capable is the VxOPC coupled with VxDCOM
not kind of misnomer ? If it is not,
what was actually done for integrating
DCOM in RTOS ?
2) The solutions for Linux (e.g. from Technosoftware require as expected DCOM
port from Software AG). Provided that
DCOM is indeed open (open means in this
case surely just the openness of interfaces)
is the other way possible: e.g. gatewaying
of DCOM to CORBA and back if needed ?

3) What about OPC XML server? Are solutions
available? Are they still DCOM-bound ?

4) What about using of SNMP for Process
Control? Have anyone collected some
expirience ?

5) What about MMS solutions for Linux?
Are they available ?

Yours sincerely
Ariel Burbaickij
 
A

Armin Steinhoff

Hallo,

>the issue. My questions are:
>1) Provided that DCOM is not real-time capable is the VxOPC coupled with VxDCOM not kind of misnomer ? If it is not, what was actually done for integrating DCOM in RTOS?>

DCOM isn't a predictable protocol .. it's based on standard TCP/IP

>2) The solutions for Linux (e.g. from Technosoftware require as expected DCOM port from Software AG). Provided that DCOM is indeed open (open means in this case surely just the openness of interfaces)>

Well .. this openess is like the openess of an open door :) You never know when this door will be closed ...

>is the other way possible: e.g. gatewaying of DCOM to CORBA and back if needed?>

Yes ... there are gateways between CORBA (not RT-CORBA) and DCOM available.

There are also available a lot of RT-CORBA implementations for real-time targets.

For integration of MS-Windows. LINUX, QNX6 and others ... we use PVM (the Parallel Virtual Machine) PVM is a cluster middleware for heterogenous distributed clusters ... these clusters are very similar to heterogenous distributed automation systems. A PVM cluster looks like a single logical machine .. so its easy to communicate between PVM nodes by message passing (UDP based secure protocol). Using the system independent API of PVM it's simple to communicate with an agent on a MS-Windows machine in order to use DCOM or OPC client services ... and at the other hand it's possible to use on e.g.
QNX6 an agent which offers RT-CORBA services ... it's just one single logical machine :)

BTW .. PVM offers also a global data base.

>3) What about OPC XML server? Are solutions available? Are they still DCOM-bound?
>4) What about using of SNMP for Process Control?

IMHO .. that's not an execelent idea.

> Have anyone collected some expirience ?
>5) What about MMS solutions for Linux? Are they available?>

AFAIK .. it's not available.

Regards
Armin Steinhoff
 
F

Frank Iwanitz

Hi,

see remarks below.

> 3) What about OPC XML server? Are solutions
> available? Are they still DCOM-bound ?

At the moment there aren't any commercial solutions available. OPC XML Server will never be DCOM bound, since the interface is WebService
based.

> 4) What about using of SNMP for Process
> Control? Have anyone collected some
> expirience ?

There are OPC Servers for SNMP in the market.
PROFInet, Ethernet/IP, IDA + Modbuson TCP are using or at least exploring SNMP.

> 5) What about MMS solutions for Linux?
> Are they available ?

Is there a need?
MMS is dead.
 
R

Ralph Mackiewicz

> > 5) What about MMS solutions for Linux?
> > Are they available ?
>
> Is there a need?
> MMS is dead.

Yes and Not hardly. You are just a little uninformed that's all. MMS is widely used world-wide for the control of electrical transmission systems and substations. In fact, if you are in the the US, Canada, China, Italy, Peru, Mexico, Columbia, and many other countries; the distribution of the electrons you are using to read this right now was likely controlled at some point using systems that used MMS to communicate via IEC60870-6 TASE.2 (aka ICCP). Applications in substations are growing as interest in UCA/IEC61850 continues to grow as well.

Regards,
Ralph Mackiewicz
SISCO, Inc.
 
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