литература / Функциональные схемы автоматизации / ANSI_ISA 5.1 2009 - Instrumentation Symbols and Identification

B.10.2 An example of a common application is the calculation of mass flow with an orifice plate primary element:

a)Separate devices or functions that require separate bubbles and tag numbers:

b)Separate devices or application software functions that do not require separate bubbles or tag numbers for each function:

FT *01

c)Integral devices or application software functions that do not require separate bubbles or tag numbers for each function:

B.11 Alarm indicators

B.11.1 Shared control and monitor functions generally allow the indication of four configurable alarms for process variables and setpoint deviations.

B.11.2 Only alarms that are to be configured are shown.

B.11.3 Instrument diagramming:

a)Process variable alarms:

--`,,```,,,,````-`-`,,`,,`,`,,`---

//^:^^#^~^^"#@::"~^$:~@""#:$@^"*^~@~$"~~""^^:@^^:#^~~\\

b)Process variable deviation from setpoint alarms:

c)Process variable deviation from setpoint and process variable alarms:

B.11.4 Functional diagramming:

a)Process variable alarms:

c)Process variable deviation from setpoint and process variable alarms:

H/L

P I

A T A

B.12 Multipoint, multivariable and multifunction instruments

B.12.1 Multipoint instruments are single or multivariable indicators or recorders that receive input signals from two (2) or more primary elements or transmitters.

B.12.2 Multivariable instruments are controllers that receive input signals from two (2) or more primary elements or transmitters and control one (1) manipulated variable.

B.12.6 A multivariable controller example drawn with bubbles for each measured variable input, the output to the final control element, and measured variable indicators:

B.12.7 variable multifunction controller example drawn with bubbles for measured variable inputs, controller and indicator functions, and final control elements, for example:

B.13 An example of instrument, functional, and electrical diagrams for a simple process

B.13.1 Process control description:

a)Process description:

1)Tank periodically fills with a liquid, in small and large volumes over long and short time periods.

b)Control description:

1)Control system design for:

a)Small volumes for long and short periods should allow tank to fill to a high level to automatically start the pump and then to stop the pump at a low level.

b)Large volumes for long periods should allow the pump to run continuously and maintain a fixed level with a level to flow cascade control loop.

--`,,```,,,,````-`-`,,`,,`,`,,`---

//^:^^#^~^^"#@::"~^$:~@""#:$@^"*^~@~$"~~""^^:@^^:#^~~\\

--`,,```,,,,````-`-`,,`,,`,`,,`---