API RP 554 2021 pdf free download

API RP 554 2021 pdf free download.Process Control Systems— Functions and Functional Specifcation Development.
3.2 business network A digital communications network that is used for general purpose business use such as desktop computing, non-process control database applications or other general purpose applications. Can be referred to as Purdue level 4. Typically, business networks use industry standard communications methods such as Ethernet. 3.3 central control room CCR Inhabited facility (typically a building) that houses plant personnel and PCS equipment to permit the operation and coordination of one or more process plants. Control rooms are not always located adjacent to the process equipment being controlled and often centralize operation of multiple process plants or areas. Trends are to locate control centers away from potential blast zones. 3.4 continuous control Control functions that are continuously and repetitively executed to control the values of process variables such as pressure, temperature, fow, etc. that are part of a continuous process such as a refning process, or within a portion of a process associated with a batch control system. 3.5 control loop That part of an instrument control system that includes the input sensor, transmitter, communication path, control algorithm, and fnal control element. Control algorithm may be executed as one of many such algorithms in a PCS or be performed by stand-alone electronic, pneumatic, or mechanical devices. 3.6 control module A processing module that performs various control and data acquisition functions in a PCS. Typically, this module is used to poll data from system I/O modules, perform basic regulatory or other control functions, and communicate I/O and control information to other modules in the PCS. 3.7 demilitarized zone DMZ A physical or logical subnetwork that contains and exposes an organization’s external-facing network services to a larger and untrusted network, i.e. the organization’s business local area network (LAN) or the Internet.
3.8 discrete control Control functions that involve on-of operations and interlocks. Discrete control variables are generally associated with thresholds above or below which a control action is taken. The control action is a discrete function such as opening or closing a valve, starting or stopping a motor, etc. 3.9 distributed control system DCS A general term used for digital PCSs that use multiple processing modules to perform the functional tasks of the system. These modules may or may not be located in physical proximity to one another. 3.10 encryption The coding and decoding of data transmissions using algorithms and encryption keys that are known only to the sending and receiving devices. A wide variety of encryption techniques and algorithms are available and have varying levels of security associated with them. 3.11 enterprise resource planning ERP Systems that are used to identify and coordinate supplies of raw materials, intermediate materials, fnished products, consumables, and other material or resources required to operate a manufacturing business. 3.12 Ethernet A networking standard that is either wireless or uses a single cable consisting of four pairs of wires to connect multiple computing devices together in a manner that does not require that any of the devices be aware of the other devices. Ethernet is an asynchronous communications method that allows messages to collide and provides for a collision detection and a random pause and retry means of allowing multiple devices to communicate. Ethernet standards are defned in the IEEE 1802.x series of standards.
3.13 feldbus A digital communication network that connects the feld sensors, transmitters, and control actuators together and to either a controller or control network. A feld bus network allows devices to send and receive messages over a shared path. Devices may send current measurements and/or diagnostic messages and receive commands or confguration data. 3.14 feld devices Any sensors, measuring devices, control elements etc. that are used to sense or directly control process conditions. Current technologies allow increased “intelligence” to be added to the feld devices, e.g. self-diagnostics, control functions, and network interconnectivity. 3.15 frewall A combination of hardware and software installed on computers and network connections to prevent undesired messages from a digital network from reaching or passing through the computers. A frewall may also hide the presence of a computer from other computers on the network. See also 3.7, DMZ. 3.16 front-end engineering design FEED Engineering activities performed during the identifcation of project scope and costs.