Point Management consists of the following modules:
Point Management Resident Process
(PTMRP)
Point Management Application
Library (PTMAP)
Point Translation Process
(PTX)
Derived Point Process (PTMDP)
Point Configuration Data
The function of each module is discussed in the following sections.
Point Management Resident Process (PTMRP)
The Point Management Resident Process (PTMRP) receives point data from other processes, responds to application requests for point data, and generates alarms when point data is outside configured limits.
Applications that need access to point data send requests to a PTMRP. These messages are sent using the Point Management Application Library (PTMAP). It is the job of PTMAP to determine which PTMRP is responsible for a specific point. Thus, applications do not need to be aware of the location of point data in a system with multiple PTMRPs.
Each PTMRP generates alarms for the points it handles.
Point Translation Process (PTX)
The Point Translation Process (PTX) manages point configuration data for applications. PTX accesses configuration data when Point Management starts up, and sends that configuration data to applications on request. Applications do not communicate directly with PTX. Application requests to PTMAP result in communications between PTX and the application.
Derived Point Process (PTMDP)
The Derived Point Process (PTMDP) provides a mechanism for summarizing information about the system, or identifying conditions that can only be recognized by evaluating several pieces of data. The Derived Point Process collects point data from the Point Management Resident Processes and uses that data to determine the value of derived points. Once the value of a derived point is established, the PTMRP that handles the point is sent the new value. The point data may then be accessed by applications.
Derived points are configured by specifying a point and an expression that is used to calculate the point's value. The expression may contain arithmetic, logical, and bitwise operators. Several Derived Point Processes may exist in a system, each handling a subset of derived point data.
Point Management Application Library (PTMAP)
The Point Management Application Library (PTMAP) is a function library through which applications access Point Management data. PTMAP accepts requests from the application, accesses configuration data through communications with PTX, and relays those requests on to a PTMRP. PTMAP receives responses back from PTMRP and provides mechanisms for sending those responses to the application.
Point Configuration Data
Defining an application that works with Point Management requires that points be defined through configuration data. Points that are device points must have Device Communications configuration as well.
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Point Management API overview. |
