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

- 61 -

ANSI/ISA-5.1-2009

Function

Equation

Definition

No

Symbol (1) (2)

Graph

Low signal select

M = X1 for X1 ≤ X2

• Output equals lesser of 2 or more

M = X2 for X1 ≥ X2

inputs.

17

<

X

M

X1

<

X2

t1

t

t1

t

High limit

M = X for X ≤ H

•

Output equals the lower

of

the

M = H for X ≥ H

input or high limit values.

18

>

X

M

H

>

t1

t

t1

t

Low limit

M = X for X ≥ L

•

Output equals the higher

of

the

M = L for X ≤ L

input or low limit values.

19

<

X

M

L

<

t1

t

t1

t

Positive bias

M = X1 + b

•

Output equal to input

plus

an

M = [-]X2 + b

arbitrary value.

20

+

X

X2

X1

M

b

+

t1

t2

t

t1

t2

t

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

ANSI/ISA-5.1-2009

- 62 -

No

Function

Equation

Definition

Symbol (1) (2)

Graph

Negative Bias

M = X1 - b

•

Output

equal

to

input minus

an

21

M = [-]X2 - b

arbitrary value.

X2

X1

−

X

M

b

−

t1

t2 t

t1

t2

t

Velocity limiter

dM/dt = dX/dt for dX/dt ≤ H, M = X

•

Output equals input as long as the

22

dM/dt = H for dX/dt ≥ H, M ≠ X

input rate of change does not

exceed

the

limit value

that

(3)

establishes the

output rate

of

dM/dt=H

a)

b)

>

X

dX/dt>H

M

change until the output again

equals the input.

(3)

a)

>

b)

t1 t2,3

t

t1 t2

t3

t

High signal monitor

(State 1) M = 0 @ X < H

•

Output

state

is

dependent

on

23

(State 2) M = 1 @ X ≥ H

value of input.

•

Output changes state when input

is equal to or higher than an

arbitrary high limit.

H

X

M

H

State

State

H

t

t1

t

t1

Low signal monitor

(State 1) M = 1 @ X ≤ L

•

Output state is

dependent on

(State 2) M = 0 @ X > L

value of input.

24

•

Output changes state when input

is equal to or lower than an

L

X

M

arbitrary low limit.

State

State

L

L

t1

t

t1

t

- 63 -

ANSI/ISA-5.1-2009

No

Function

Equation

Definition

Symbol (1) (2)

Graph

(State 1) M = 1 @ X ≤ L

•

Output states are dependent on

25

High/low signal monitor

(State 2) M = 0 @ L < X < H

value of input.

(State 3) M = 1 @ X ≥ H

•

Output changes state when input

is equal to or lower than an

arbitrary low limit or equal to or

HL

X

M

higher than an arbitrary high limit.

H

State

State

State

HL

L

t1

t2 t

t1

t2

t

Analog signal generator

No equation

•

Output equals a variable analog

26

signal that is generated:

A

a.Automatically and is

not adjustable by operator.

No graph

b. Manually and is adjustable

A

by operator.

Binary signal generator

No equation

•

Output equals an on-off binary

27

signal that is generated:

a. .Automatically and is

B

No graph

not adjustable by operator.

b. Manually and is adjustable

B

by operator.

Signal transfer

(State 1) M = X1

•

Output

equals input

that is

28

(State 2) M = X2

selected by transfer.

•

Transfer

actuated by

external

X

M

X1

signal.

X2

State

State

T

t1

t

t1

t

Analog signal transfer

X

X1

M

X2

T

State

State

t1

t

t1

t

Binary signal transfer