Description

Function description

This function block should be used when two actuators are in use to enable coverage of the whole area (when two operating points are far apart: one below and one above).

The controller is also suitable for three-point step action controls, i.e. for cases where the two actuators work in opposition (one heats, the other cools).

and can be configured as additional parameters.

Properties

The function block SPLRG has the following properties:

The possibility of controlling a dead zone or a transition zone where the properties of both actuators are in line
The IN input is expressed as a percentage (0-100%) and the outputs OUT1 and OUT2 are expressed in physical units.

Representation in FBD

Representation:

Representation in LD

Representation:

Representation in IL

Representation:

CAL SPLRG_Instance (IN:=ValueToBeBrokenDown, 
    PARA:=Parameters, OUT1=>InstructionByActuator1, 
    OUT2=>InstructionByActuator2, STATUS=>StatusWord)

Representation in ST

Representation:

SPLRG_Instance (IN:=ValueToBeBrokenDown, 
    PARA:=Parameters, OUT1=>InstructionByActuator1, 
    OUT2=>InstructionByActuator2, STATUS=>StatusWord) ;

Parameter description SPLRG

Input parameter description:

Parameter	Data type	Meaning
IN	REAL	Value to be resolved (0 to 100%)
PARA	Para_SPLRG	Parameter

Output parameter description:

Parameter	Data type	Meaning
OUT1	REAL	Manipulated variable for actuator 1
OUT2	REAL	Manipulated variable for actuator 2
STATUS	WORD	Status word

Parameter description Para_SPLRG

Data structure description

Element	Data type	Meaning
out1_th1	REAL	Input value IN, for which the following applies: OUT1 = out1_inf
out1_th2	REAL	Input value IN, for which the following applies: OUT1 = out1_sup
out1_inf	REAL	Lower threshold of the output OUT1
out1_sup	REAL	Upper threshold of the output OUT1
out2_th1	REAL	Input value IN, for which the following applies: OUT2 = out2 _inf
out2_th2	REAL	Input value IN, for which the following applies: OUT2 = out2_sup
out2_inf	REAL	Lower threshold for output OUT2
out2_sup	REAL	Upper threshold for output OUT2

Base	Lower limit	Upper limit
Hexadecimal	16#0	16#FFFF
Octal	8#0	8#177777
Binary	2#0	2#1111111111111111

Data	Representation in one of the bases
0000000011010011	16#D3
1010101010101010	8#125252
0000000011010011	2#11010011

REAL

The REAL type is encoded in a 32 bit format.

The possible value ranges are shown in the figure below:

When a result is:

between -1,175494e-38 and 1,175494e-38, it is considered to be a DEN;
less than -3.402824e+38, the symbol -INF (for - infinity) is displayed;
greater than +3.402824e+38, the symbol INF (for + infinity) is displayed;
undefined (square root of a negative number), the symbolNAN is displayed.

NOTE: The IEC 559 standard defines two classes of NAN: the silent NAN (QNAN) and the signaling NAN (SNAN). A QNAN is a NAN with a most significant fraction bit while an SNAN is a NAN without a most significant fraction bit (bit number 22). QNANs can be propagated via most arithmetic operations without throwing an exception. As for SNANs, they generally indicate n invalid operation when they are used as operands in arithmetic operations (see %SW17 and %S18).

NOTE: When a DEN (non-standardized number) is used as an operand, the result is not significant.