520 likes | 871 Vues
PI Software Development Kit. PI-SDK. Agenda. The expanded class hierarchy Data access with the PI-SDK The PITimeServer library Multi-threading and the PI-SDK OSI and the PI-SDK Troubleshooting tips Coming attractions Questions. Class Hierarchy. PI-SDK 1.0 The current release
E N D
PI Software Development Kit PI-SDK
Agenda • The expanded class hierarchy • Data access with the PI-SDK • The PITimeServer library • Multi-threading and the PI-SDK • OSI and the PI-SDK • Troubleshooting tips • Coming attractions • Questions
Class Hierarchy • PI-SDK 1.0 • The current release • PI-SDK 1.1 • PI-Batch and the Module Database • PI-SDK 2.0 • Data Access
Data Access with the PI-SDK • PIData and ListData • The access paths • Value Format • What do values look like now? • PIValues capabilities • What can I do with the values? • Writing Values
Data.RecordedValues() • Start time and end time as Variant • Boundary type • Filter expression • Show filtered • Asynchronous • Returns a PIValues collection
Writing values to PI • UpdateValue and UpdateValues • RemoveValues
Demo • Retrieving PIValues
Advanced Topics • Event pipes • Using asynchronous calls
Problem: Alarm Application • Your app must catch every event • But you can’t listen all the time • Polling may miss an event Oops
The EventPipe Object • Get from a PIPoint or a PointList • Collects value changes • Count property • Take, Peek methods • First In, First Out (FIFO). • OnNewValue event • Can be throttled to avoid event overload
Problem: Long Queries • Long blocking calls inhibit user response and slow down your application • But breaking the query into small chunks may reduce efficiency • Server does redundant work • More network calls
PIAsynchStatus Object • Lets you monitor the status of a query • Sends an event when done • Provides for progress bar • Many calls can be asynchronous • PIPoint.Data archive retrieval • PointList.Data archive retrieval • PIValues.RecordSet • Server. GetPoints, GetPointsSQL • PISDK.GetPoints • MessageLog.List
Using PIAsynchStatus Dim WithEvents asy As PIAsynchStatusSet asy = New PIAsynchStatus Dim pv As PIValuesSet pv = MyPoint.Data.RecordedValues (“*-1h”, “*”, , , , asy)Rem pv.Count should be zero... Private Sub a_OnStatusChange If asy.Status = csCompleted Then ...
Time in the SDK • Classic problems: summer time, time zones, clock drift • The solution: PITimeServer
Time—The Problems • Summer time (DST) • What are the rules for this location? • What were the rules last year? • We must track historic changes • Does my computerfollow the rules? • It probably doesn’t even know them. • Even if it does (NT), it may not follow them.
Time—The Problems • Time zones • Servers can be in various time zones • Clients can be in a different time zone from any server • Queries must be interpreted in the time zone of the server
Time—The Problems • Clock drift • Even in the same time zone, the client clock may not be exactly the same as the server clock • Real-time data inputs to a server should be timestamped with the server clock, i.e. adjusted for clock drift • Historical inputs should not be adjusted for clock drift
Time—The Problems • Time intervals (days, months, shifts) • Is 1day = 24hours? • Not always, if you observe summer time • On March 30, what does this mean?“*-1month” • Can I define my plant shift schedule?
Time—The Solutions • PITimeServer • Independent COM server DLL • Does not require PISDK.DLL for support • Defines these objects: • PITime, PITimeFormat, DynamicTime • PITimeZoneInfos, PITimeZoneInfo • DeviceTimeZones • TimeIntervals, ITimeInterval
PITimeZoneInfo object • Encapsulates time zone information • Offset from UTC • Summer/winter time change rules • Historical changes in rules • Every device is assigned one • Server, client, instrument • PITimeZoneInfos collection • All known time zones on this client • User can add or remove zones
Time Objects: PITime • Lightweight, server-independent • Translates wallclock to UTC using client-node time zone information • Operations: • UTCSeconds property • UTCFileTime property • LocalDate property • SetToCurrent method
Time Objects: PITimeFormat • Superset of PITime • Knows its time zone • TimeZoneInfo property • Parses time strings • Microsoft format (localized) or PI format • Formats output strings • Works with time intervals • “subtract 3 weeks”
Time Objects: DynamicTime • Superset of PITimeFormat • Represents a moving time, such as “*” or “*-4.5 hours” • Property values change constantly • Referenced to a known clock source • Server clock • Client clock • Device clock, user-defined
ITimeInterval Object • Represents a kind of interval • Name, ShortName: month, mo • MemberLo, MemberHi: 1, 12 • Member(Short)Name: January, Jan, … • Operations: given a time— • What month is it? • When did that month start? • Add or Subtract n months • How many months between two times?
TimeIntervals Collection • Contains all intervals known on the client • Interval servers • Installed via registry entry • Standard: year, month, day, week, weekday, yearday, hour, minute, second • User-defined: whatever you want • Shift, Plant day • Fiscal year/month/week/quarter
Threading • Release 1 was apartment-threaded • Release 2 will be free-threaded • Apartment-neutral • Uses the Free-Threaded Marshaler (FTM)
If It Ain’t Broke… • Apartment-threading works correctly • But performance is unacceptable
Why Should I Care? • Multi-threaded design is natural for many applications • Interfaces—thread per scan class • Displays—thread per graphic • Today, this mostly affects C++ developers • VB7 will support free-threading
OSI and the PI-SDK • Redesigns of existing products • New products in development • Existing products
Redesigns for the PI-SDK • PI-ProcessBook • PI-DataLink • Sigmafine • PI-BatchView • PI-Profiles
New Applications • PI-PointBuilder • PI-AlarmView • Real-time SQC Point Manager • PI-AutoPointSynch These are demonstrated Tuesday afternoon.
Controls and Libraries • PI-BatchView 3.0 • Module Database Controls • Tag search
New Interfaces • PI-Perfmon • OPC • ICCP
Existing Products • Embedded PI systems • Point creation • User/Group management • Batch Event File Interface • Integration with batch systems • UNIINT 3.2.0 • Flexible attribute retrieval • PIlog32.dll and sdkreg.dll
Troubleshooting Tips • After the setup • Read the setuppisdk.log • Run AboutPI-SDK • The new apisnap
AboutPI-SDK Hidden Connect Button Version Info Timeout Info
Connecting Manage your Servers Here
Communication Layers • What’s a pinetmgr and do I need one? • What’s a redirector and how is it configured? • ~\pipc\dat\pisubsys.cfg
Pisubsys.cfg • Redirected • Generic_local hostname:portnumber For example: Generic_local bilbo:5450 • Local pinetmgr • Generic_local \\.\pipe\rendevouz file path For example: Generic_local \\.\pipe\e:\PI\dat\piv3.rdz
What if? • Remember AboutPI-SDK = apisnap • Can’t run AboutPI-SDK • Check error message • Check setup
What if? • Can’t connect • Is server running? • Client side • Ping, apisnap, ProcessBook • Server side • Check services.(Net start, or services applet) • Does piconfig work? • Does pisnap work? • Is the local pinetmgr service running? • Try using a redirector
What if? • Err.Description • Often includes server specific errors • Intermittent errors • If it used to work, suspect the server • PI-SDK web page • Reported Problems • http://support.osisoft.com/progtools/pisdk/
Coding Problems • Try the examples in the help file • Try the sample applications on the web • Isolate the problem • Send small examples that demonstrate the problem to tech support.