Description

Function description

The function block RAMP makes it possible to move in ramp form from an initial setpoint value to a particular target value. The gradients of positive and negative ramps can vary.

A signal (DONE output) indicates the user, whether a target value has already been reached or if the ramp had been implemented.

and can be configured as additional parameters.

Representation in FBD

Representation:

Representation in LD

Representation:

Representation in IL

Representation:

CAL RAMP_Instance (RSP:=RampTargetValue, PARA:=Parameters,
    TR_I:=InitialRampValue, TR_S:=RampInitializationOrder,
    SP=>Output, DONE=>ProgressFlag, STATUS=>StatusWord)

Representation in ST

Representation:

RAMP_Instance (RSP:=RampTargetValue, PARA:=Parameters,
    TR_I:=InitialRampValue, TR_S:=RampInitializationOrder,
    SP=>Output, DONE=>ProgressFlag, STATUS=>StatusWord) ;

Parameter description RAMP

Input parameter description:

Parameter	Data type	Meaning
RSP	REAL	Target value of the ramp
PARA	Para_RAMP	Parameter
TR_I	REAL	Initial value of the ramp
TR_S	BOOL	Initialization command of the ramp

Output parameter description:

Parameter	Data type	Meaning
SP	REAL	Output
DONE	BOOL	"1": the target value has been reached "0": the ramp function has been executed
STATUS	WORD	Status word

Parameter description Para_RAMP

Data structure description

Element	Data type	Meaning
inc_rate	REAL	Positive gradient in units per second (≥0)
dec_rate	REAL	Negative gradient in units per second (≥0)

EN stands for ENable; it is an optional block input. When the EN input is enabled, an ENO output is set automatically.

If EN = 0, the block is not enabled; its internal program is not executed, and ENO is set to 0.

If EN = 1, the block's internal program is run and ENO is set to 1. If an error occurs, ENO is set to 0.

If the EN input is not connected, it is set automatically to 1.

ENO

ENO stands for Error NOtification; this is the output associated with the optional input EN.

If ENO is set to 0 (because EN = 0 or in case of an execution error):

the status of the function block outputs remains the same as it was during the previous scanning cycle that executed correctly;
the output(s) of the function, as well as the procedures, are set to "0".

WORD

The type WORD is encoded in a 16 bit format and is used to perform processing on series of bits.

This table shows the upper/lower limits of each of the bases that can be used:

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

Examples of representation

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.