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Rank: Advanced Member
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Joined: 7/16/2008
Posts: 35
Location: UK
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Hello there, I'd be interested to know what systems are feeding your PI servers! I am supporting several PI servers and they all seem to be connected to various different systems such as Bailey, Siemens, Honeywell PHD, DeltaV, ABB MCS, etc etc. I don't know exactly about all these systems but I'd be interested to know if anyone works with these systems and also if there are any particular control systems you find work very well with PI, and any common problems you experience etc. Most of our systems are Windows, but we still have one or two old VMS Net Nodes, does anyone support this type of setup? Any tips/advice? Who ate all the PIs?
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OSIsoft vCampus is a subscription-based, online offering that consists of providing everything people need to develop applications on the PI System. We invite you to take a "tour" of the OSIsoft Virtual Campus - also feel free to consult the FAQ or contact OSIsoft vCampus for more details.
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 612
Location: Cheshire, United Kingdom.
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Hi Macaroni and welcome. Most PI systems I have worked with now are generally fed via OPC so I pretty much don't bother looking any further down the chain as they are managed by DCS engineers but I have connected to Honeywell PHD, Experian, whole host of Foxboro systems, Siemens etc. At present we experience sporadic problem with OPC connectivity - the OPC server will stop sending data (reboot/crash etc) and then reconnect but data never makes it back across. A restart of the PI OPC client is required - nothing big but annoying more than anything else. I spent about 6 months retiring a load of VMS boxes and replacing with PI/DCS which was fun but a tricky situation for the client's business users to let go of VMS. Once you start to explain the benefits of PI clients on Windows, in particular Processbook they soon change their minds :-) My tip for VMS would be to retire them but then again being fairly young I have never been a fan of VMS. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Advanced Member
Groups: Member
Joined: 7/16/2008
Posts: 35
Location: UK
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Thanks RJK. interesting to read! Funnily enough, we have some servers which are connected by OPC, and these are the most unreliable out of the bunch!! Seems to be the same problem you are mentioning though, after a problem on the OPC server, we have to restart the OPC server, and we are using OPC Tunneller software from Matrikon to move the data from the OPC server to PI, so this service needs restarted. We ran into a funny problem whereby when we rebooted the PI server one day, all the data stopped flowing and our tags could not be reconnected. We noticed a lot of errors in the OPC tunneller logs and thought this may be the problem, but we managed to work around the problem by setting all tags offscan, and then gradually enabling the tags in small blocks (500 or so a time) This was a small system (8000 tags or so) but a very funny problem and one we have not yet resolved. We are several versions out of date with both the tunneller software and the OPC interfaces, so obviously thats the suggestion from both OSI and Matrikon...UPGRADE! We'll see if this fixes the problem! The VMS servers we are seeing are just Net Nodes, sitting between old control systems (like Bailey) and the PI server. I'm sure these could be replaced, but our clients are not the type to ever want to spend any money (despite astronomical profits of course!) Interestingly, the VMS nodes are the least problematic, and at last count ran 3 years without an outage! (Im sure this could have went longer, but the plant were carrying out essential electrical maintenace!) One annoyance I've come across (in case anyone finds this searching VMS and PI!) is that when we have an outage on the PI server receiving from this node (as its Windows, this happens more than we'd like!) then a service on the VMS node seems to time out, which i think is called PINETSYNC. Basically, when we create new tags, these are never picked up on the node, and can sit at "point created" forever until the service is started again. Other than that, I would say the VMS nodes are fantastic, but yes I can see them going very soon, and only one person in our team really has experience in VMS (most of us are thankfully too young to have had to deal with them!!) Who ate all the PIs?
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Rank: Advanced Member
Groups: Member
Joined: 7/23/2008
Posts: 38
Location: Cheshire, UK
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Hi MarconiPI,
I work with a number of PI systems spanning a number of sites across Europe and the US. Typically we are connected to one of two systems
- DeltaV DCS's using PI to PI connectivity for continuous data, OPC Alarm and Event for the Alarm and Event Data and PI EVT for Batch data
- Rockwell PLC's using OPC DA connectivity for continuous data, PI-UFL for alarm and diagnostics log data and PI-BaGen for Batch data
Recently I've been working with DeltaV to PI using the OPC HDA interface.
In addition to these there are a number of other systems that we have PI interfacing to on other sites such as Foxboro I/A, Maximo (Asset Maangement System), and later this year the plan is to provide an interface link to an OPUS Electrical Monitoring system using PI-UFL.
Sorry guys, but despite people complaining about OPC I've yet to see any issues once set up and running in a production environment, although I do tend to be very rigorous with DCOM setups, security and access permissions during the installation stage. I had one occasion on an OPCAE server where we stopped getting data but this was down to someone turning a DCS service off during DCS trouble shooting and not starting the service up again - so not really an OPC issue as such.
Regards,
Burnikell1
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Rank: Advanced Member
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Joined: 7/16/2008
Posts: 35
Location: UK
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As you mention DCOM I presume you are not using Matrikon OPC Tunneller? I'm starting to think perhaps its the weak link in the chain  Who ate all the PIs?
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 612
Location: Cheshire, United Kingdom.
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Hi Macaroni, Burnikell1, Yes where I have seen OPC irregularities Matrikon Tunneler has been used - it is used extensively at one site where I worked with PI/DCS links. When I get some spare time I will try and replicate the problem using both methods to see if there is a chink in the tunnelers armour :-) RJK Solutions. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Advanced Member
Groups: Member
Joined: 7/23/2008
Posts: 38
Location: Cheshire, UK
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In my experience OPC Tunneling technology is usually adopted when issues already exist, (which may or may not be down to DCOM issues) or their is a lack of confidence/knowledge in being able to configure DCOM.
A typical scenario would be using a third party opc client remotely to connect to a venders opc server. The vendor will normally issue a recommendation that the client shouldn't be put on his server box else warrentry is compromised, and won't necessarily release the details required to configure the OPC client on a remote box.
OPC Tunneling bypasses DCOM and uses TCP/IP directly therefore bypassing the security around DCOM.
My suspicion is that many use tunneling technology to avoid DCOM, but in doing so fail to evaluate other issues that may be inherent in the system such as the correct setup of OPC Servers ie the configuration of the appropiate number of groups and their scan rates.
The definition below is provided by the OPC Training Institute:
OPC Tunneling: A concept that enables OPC communication to bypass DCOM and use TCP/IP directly. This enables OPC communication to take place where DCOM would be inappropriate. This would be needed when the available network is highly unreliable (marked by a high number of communication disruptions), low bandwidth, or firewalls that block DCOM communication. OPC Tunneling also enables users to bypass most (and sometimes all) DCOM configuration. Therefore, OPC Tunneling might be easier to use for people who do not know how to configure DCOM
Regards,
Burnikell1
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Rank: Advanced Member
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Joined: 7/16/2008
Posts: 35
Location: UK
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Some interesting points, and I agree this may be seen as somewhat of a shorcut / set and forget. We have inherited most of our PI servers and the technology behind them, and such are the budgets and time restraints on us that the philosophy of "if it ain't broke.." often applies. We were looking at removing the tunneller in one setup, but that last quote makes it clear to me that the main reason we have OPC tunneller will be due to the tight firewall setup between the control network and corporate network. In this respect, tunnelling makes sense. RJ, I notice you are also connecting to Uniformance PHD, are you connecting to the PHD OPC server or using a PHD interface? I believe we use a PHD interface in one site, but OPC in the other. The site we use OPC in also has a PItoPI interface to a consolidated server, so I wonder if this is the reason they didn't use the PHD interface. Can more than one interface use port 5450? This port (plus RDP and the Tunneller port) are the only ports the firewall team would ever consider opening to us... Who ate all the PIs?
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Rank: Administration
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Joined: 6/20/2008
Posts: 612
Location: Cheshire, United Kingdom.
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For PHD at 1 client they were using a PHD com connector, so to go across their firewall they are using PHD2PHD, SQLNet. They are now looking at moving to OPC as there is a performance hit (maybe even a bug) with the com connector and the PI server is rejecting requests from PI clients as it goes into its "safe mode" at different intervals. This whole setup was working great until something changed one day and of course no one knows what actually changed / tipped the balance on this. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Advanced Member
Groups: Member
Joined: 7/16/2008
Posts: 35
Location: UK
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Sounds quite worrying! I'm glad we're not the only ones who experience these sort of nightmares  Maybe best to stick with OPC then, thanks for the heads up! Who ate all the PIs?
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Rank: Newbie
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Joined: 8/5/2008
Posts: 1
Location: UK
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Hi everyone, First of all, thanks to RJK for for the forum  I also look after several PI servers which connect to: Foxboro I/A 50 and 70 series (NT and Solaris) DeltaV (using PI-OPC) Intellution iFix (custom interface) I also use PI-SNMP and PI-NT Performance Monitor interfaces a lot. We have a dedicated 3 server PI system which monitors our IT Infrastructure accross the globe. This way of using PI has been really popular with our Network guys who are now PI lovers! Recently I have connected our site weather monitoring station to PI using a custom interface. Also hooked up some Janitza smart meters to PI using a PI-OPC interface.
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 612
Location: Cheshire, United Kingdom.
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hi dewipi and welcome! glad to see there are plenty of pi people out there and so far seems to be a few in the uk too. for a client we connected a weather system few years ago and got some neat processbooks made. In fact I made a wind direction dial by just using a single line symbol and some math! it was complicated by the fact a line symbol is all top, left, height and width properties. Then of course I simply just used multistated symbols to simplify it and no vba was needed. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Member
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Joined: 7/23/2008
Posts: 25
Location: Milan, Italy
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Interesting Rhys, but just wondering why you didn't use the Rotation property of a single line in ProcessBook? doug www.definitconsulting.com
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Rank: Advanced Member
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Joined: 7/23/2008
Posts: 38
Location: Cheshire, UK
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Hi MacaroniPI,
There shouldn't be an issue with tight firewalls, typically I find the problem is getting IT guys to understand Automation networks and Automation guys to understand IT networks. Usually systems are at either end of the security spectrum i.e. completely locked down or completely left open. The solution is a DMZ locking down the way traffic flows through the system which can be implemented using firewalls at either end of the PI server. The firewall can be configured to allow only specified traffic in or out.
I think the problem is often that firewalls are configured by IT departments who in the modern world tend to be outsourced to third party organisations due to being non core business; as a consequence the IT skills tend to be based around a little knowledge and what is on crib sheets rather than any true in-depth experience. Trying to explain the principles of network security in terms of connecting automation networks to IT networks can be extremely frustrating when the other guy just can't grasp it 'cause it's not on his sheet.
In my experience this is part of the reason people use tunnelling technologies, not necessarily because they need to but rather because they don't know enough not to.
The thing to consider is that Tunnelling technology opens up security in order to bypass DCOM. With DCOM you have the benefits (?) of a widely used and supported Microsoft technology incorporating the Microsoft Security models; when you move to Tunnelling you bypass some of this security and use TCP/IP directly to route the connection. This (as it was explained to me) provides security only by the fact that the technology is relatively new and small fry in respect of the IT world in general i.e. it is secure by being obscure.
Regards,
Burnikell1
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Rank: Administration
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dgcoene wrote:Interesting Rhys, but just wondering why you didn't use the Rotation property of a single line in ProcessBook?
doug With the rotation property you still need to move and place the line so that it appears to originate from the same point, the middle of a compass. Plus, we were given a bit of a challenge by the client - in a way a kind of test that we passed :-) Principal Consultant
Real-Time Data Management @ Wipro Technologies
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