Doc: ps2001-5-1101-001 Rev: R02. 00
A description of the Project
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1486357009-URS, URS
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- 2.1.1 Standard Modules
| A description of the Project At its most fundamental level, the PAL will be a library of software modules that control the fundamental aspects of an industrial plant such modules would for example read the value of an instrument, operate a valve or drive, perform a calculation c. Within this Project, such software modules will be referred to as standard modules, these will be fixed modules that perform a particular function and are identical across all software installations. The PAL will also contains application specific modules these will contain software that is applicable to the plant being controlled. For example, if a project were to control five valves, there would bean application module that called the standard valve module five times and each instance would link the standard module to the particular signals and internal storage locations associated with the valve in question. 2.1.1 Standard Modules Standard modules will be modules that carryout a particular function an example would be a module that controls the operation of a valve, such a module would do the following • Open and close the valve when commanded to do so • Determine if the valve is in a fault condition (i.e. the valve did not open when commanded to do so) • Provide status information about the valve allowing other systems (supervisory systems such as SCADA, HMI, c) to display the condition of the valve (i.e. opened, opening, closed, closing, fault, interlocked c) Doc PS Rev R 15-71 The module would be configurable to accommodate different types of valves and signalling arrangements • Different arrangements of position feedback (none, open only, closed only or both open and closed) • Different opening and closing times • Handle external fault signals (typical for motorised valves) • Accommodate different energising states (i.e. energise to open or energise to close) • Manage different interlock arrangements and signals The module would also determine how the operator could interface with the valve • Provide manual control (operator can take direct control of the valve) • Restrict specific manual control functions (this ranges from full control using simulation to override faults, to no control whatsoever, even restricting the display of faceplate interfaces) • Allow or restrict the operator from changing operating parameters associated with the valve The PAL will have many of these types of modules in fact this type of modules will makeup the bulk of the PAL software. The standard modules within the PAL will be fixed modules, the software within these modules will be written, tested and validated as part of this Project and at only that point will the modules be released for use. Once released, the modules must not be modified or changed in any unauthorised way, to do so would invalidate the software. 16-71 Doc PS Rev R The standard modules will coverall aspects of a control system, at a minimum this will include the following • System (internal) signal generation • Instrumentation • Safety and interlock systems • Sequence control • Device handling (valves, drives, control loops c) • Alarm handling • Communications There will also be various standard subroutines that, while not associated with any particular piece of equipment, will provide common software functions (e.g. timing functions, conversions c) that will be available to all modules within the controller. The different options available to a standard module should be selectable by the use of particular parameters passed to the module that either activate or deactivate specific modes of operation or pass configuration values to the module (e.g. opening and closing times of a valve, operating range of an instrument. Common arrangements and mechanisms for creating and organising data structures, passing data, and the numbering and naming conventions for modules and variables will be established to give the software a common look and feel Download 1.5 Mb. Share with your friends:
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