Description

Function description

This function block is used to split a digital output. A common usage is duplicating a PID output to an actuator.

A dead band can be applied to the deviation between the IN input and the positional copy.

The manual operating mode enables the control to operate with or without positional feedback (by feeding the output to the input, no deviation will occur on changeover to auto; therefore the start will be smooth).To switch smoothly from manual mode to auto mode in servo control, feed an increasing or decreasing ramp to the setpoint input.

and can be configured as additional parameters.

Application possibilities

The function block will mainly be used with the following applications:

For the control of an analog output, which is not controlled via a servo loop (open loop).
Servo loops, with which the control output and the user controlled output have inserted a processing operation.
For scanning of the output controlled controller, if the scanning period exceeds 1 to 2 seconds.
For control of a server motor: the function block MS_DB is in this case the controller block in order to insert the server motor.

Representation in FBD

Representation:

Representation in LD

Representation:

Representation in IL

Representation:

CAL MS_Instance (IN:=Instruction, FORC:=OperatingModeFlag, 
    MA_FORC:=OperatingModeFORC_1, 
    MAN_AUTO:=OperatingModeFORC_0, PARA:=Parameters, 
    TR_I:=InitializationInput, TR_S:=InitializationType, 
    RCPY:= PositionalCopy, 
    OUT:=AbsoluteOutput, OUTD=>IncrementalOutput, 
    MA_O=>CurrentBlockOperatingMode, STATUS=>StatusWord)

Representation in ST

Representation:

MS_Instance (IN:=Instruction, FORC:=OperatingModeFlag, 
    MA_FORC:=OperatingModeFORC_1, 
    MAN_AUTO:=OperatingModeFORC_0, PARA:=Parameters, 
    TR_I:=InitializationInput, TR_S:=InitializationType, 
    RCPY:= PositionalCopy, 
    OUT:=AbsoluteOutput, OUTD=>IncrementalOutput, 
    MA_O=>CurrentBlockOperatingMode, STATUS=>StatusWord) ;

Parameter description MS

Input parameter description:

Parameter	Data type	Meaning
IN	REAL	Manipulated variable used in automatic mode
FORC	BOOL	"1": The mode manual/automatic will be entered via MA_FORC "0": The mode manual/automatic will be entered via MAN_AUTO
MA_FORC	BOOL	Mode manual/automatic (if FORC = 1) "1": Automatic operating mode "0": Manual mode
MAN_AUTO	BOOL	Mode manual/automatic (if FORC = 0) "1": Automatic operating mode "0": Manual mode
PARA	Para_MS_DB	Parameter
TR_I	REAL	Initialization input
TR_S	BOOL	Initialization command
RCPY	REAL	Positional feedback (0 to 100%)

Input / output parameter description:

Parameter	Data type	Meaning
OUT	REAL	Absolute output

Output parameter description:

Parameter	Data type	Meaning
OUTD	REAL	Incremental output: Difference between the present output and the output of the previous execution
MA_O	BOOL	Current mode of the function block (0: Manual, 1: Automatic)
STATUS	WORD	Status word

Parameter description Para_MS_DB

Data structure description

Element	Data type	Meaning
out_min	REAL	lower limit value of the output
out_max	REAL	upper limit value of the output
inc_rate	REAL	Increasing ramp at the changeover manual/automatic (units per second)
dec_rate	REAL	Decreasing ramp at the changeover manual/automatic (units per second)
outbias	REAL	Value of the bias
use_bias	BOOL	"1": Enable the bias
bumpless	BOOL	"1": Settings of the bias with changeover manual/automatic (bumpless)
dead_band	REAL	Dead zone on deviation
en_rcpy	BOOL	"1": Function with positional feedback (including RCPY)

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.