Saturation
Limit input signal to the upper and lower saturation values
Libraries:
Simulink /
Commonly Used Blocks
Simulink /
Discontinuities
HDL Coder /
Discontinuities
Description
The Saturation block produces an output signal that is the value of the input signal bounded to the upper and lower saturation values. The upper and lower limits are specified by the parameters Upper limit and Lower limit.
Input  Output 

Lower limit ≤ Input value ≤ Upper limit  Input value 
Input value < Lower limit  Lower limit 
Input value > Upper limit  Upper limit 
Examples
Using the Quantizer and Saturation blocks in sldemo_boiler
This example shows how the Quantizer and Saturation blocks are used in the model ex_sldemo_boiler. The ADC subsystem digitizes the input analog voltage by:
Multiplying the analog voltage by 256/5 with the Gain block
Rounding the value to integer floor with the Quantizer block
Limiting the output to a maximum of 255 (the largest unsigned 8bit integer value) with the Saturation block
Ports
Input
Port_1 — Input signal
scalar  vector
The input signal to the saturation algorithm.
Data Types: double
 single
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
 fixed point
Output
Port_1 — Output signal
scalar  vector
Output signal that is the value of the input signal, upper saturation limit, or lower saturation limit.
Data Types: double
 single
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
 fixed point
Parameters
Main
Upper limit — Upper saturation boundary for the input signal
0.5
(default)  scalar  vector
Specify the upper bound on the input signal. If the input signal is greater than this boundary, then the output signal is set to this saturation value. The Upper limit parameter is converted to the output data type using roundtonearest and saturation. Upper limit must be greater than the Output minimum parameter and less than the Output maximum parameter.
Programmatic Use
Block Parameter:
UpperLimit 
Type: character vector 
Value: real scalar or vector 
Default:
'0.5' 
Lower limit — Lower saturation boundary for the input signal
0.5
(default)  scalar  vector
Specify the lower bound on the input signal. If the input signal is less than this boundary, then the output signal is set to this saturation value. The Lower limit parameter is converted to the output data type using roundtonearest and saturation. Lower limit must be greater than the Output minimum parameter and less than the Output maximum parameter.
Programmatic Use
Block Parameter:
LowerLimit 
Type: character vector 
Value: real scalar or vector 
Default:
'0.5' 
Treat as gain when linearizing — Specify the gain value
On
(default)  Boolean
Select this check box to cause the commands to treat the gain as 1. The linearization commands in Simulink^{®} software treat this block as a gain in state space. Clear the box to have the commands treat the gain as 0.
Programmatic Use
Block Parameter:
LinearizeAsGain 
Type: character vector 
Values: 'off' 
'on' 
Default: 'on' 
Enable zerocrossing detection — Enable zerocrossing detection
on
(default)  off
Select to enable zerocrossing detection. For more information, see ZeroCrossing Detection.
Programmatic Use
Block Parameter:
ZeroCross 
Type: character vector  string 
Values: 'off' 
'on' 
Default: 'on' 
Sample time (1 for inherited) — Interval between samples
1
(default)  scalar  vector
Specify the time interval between samples. To inherit the sample time, set this
parameter to 1
. For more information, see Specify Sample Time.
Dependencies
This parameter is visible only if you set it to a value other than
1
. To learn more, see Blocks for Which Sample Time Is Not Recommended.
Programmatic Use
Block Parameter:
SampleTime 
Type: string scalar or character vector 
Default:
"1" 
Signal Attributes
The Data Type Assistant helps you set data attributes. To use the Data Type Assistant, click . For more information, see Specify Data Types Using Data Type Assistant.
Output minimum — Minimum output value for range checking
[]
(default)  scalar
Lower value of the output range that Simulink checks.
Simulink uses the minimum to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Specify Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixedpoint data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).
Note
Output minimum does not saturate or clip the actual output signal. Use the Saturation block instead.
Programmatic Use
Block Parameter:
OutMin 
Type: character vector 
Values: '[ ]' 
scalar 
Default: '[ ]' 
Output maximum — Maximum output value for range checking
[]
(default)  scalar
Upper value of the output range that Simulink checks.
Simulink uses the maximum value to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Specify Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixedpoint data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).
Note
Output maximum does not saturate or clip the actual output signal. Use the Saturation block instead.
Programmatic Use
Block Parameter:
OutMax 
Type: character vector 
Values: '[ ]' 
scalar 
Default: '[ ]' 
Output data type — Specify the output data type
Inherit: Same as input
(default)  Inherit: Inherit via back propagation
 double
 single
 int8
 int32
 uint32
 int64
 uint64
 fixdt(1,16,2^0,0)
 <data type expression>
 ...
Choose the data type for the output. The type can be inherited, specified directly, or
expressed as a data type object such as Simulink.NumericType
. For
more information, see Control Data Types of Signals.
Programmatic Use
Block Parameter:
OutDataTypeStr 
Type: character vector 
Values: 'Inherit: Same as
input' , 'Inherit: Inherit via back
propagation' , 'single' , 'int8' ,
'uint8' , int16 ,
'uint16' , 'int32' ,
'uint32' , 'int64' ,
'uint64' , fixdt(1,16,0) ,
fixdt(1,16,2^0,0) ,
fixdt(1,16,2^0,0) . '<data type
expression>' 
Default: 'Inherit: Same as
input' 
Lock output data type setting against changes by the fixedpoint tools — Option to prevent fixedpoint tools from overriding Output data type
off
(default)  on
Select this parameter to prevent the fixedpoint tools from overriding the Output data type you specify on the block. For more information, see Use Lock Output Data Type Setting (FixedPoint Designer).
Programmatic Use
Block Parameter:
LockScale 
Type: character vector 
Values:
'off'  'on' 
Default:
'off' 
Integer rounding mode — Specify the rounding mode for fixedpoint operations
Floor
(default)  Ceiling
 Convergent
 Nearest
 Round
 Simplest
 Zero
Choose one of these rounding modes.
Ceiling
Rounds both positive and negative numbers toward positive infinity. Equivalent to the MATLAB^{®}
ceil
function.Convergent
Rounds number to the nearest representable value. If a tie occurs, rounds to the nearest even integer. Equivalent to the FixedPoint Designer™
convergent
function.Floor
Rounds both positive and negative numbers toward negative infinity. Equivalent to the MATLAB
floor
function.Nearest
Rounds number to the nearest representable value. If a tie occurs, rounds toward positive infinity. Equivalent to the FixedPoint Designer
nearest
function.Round
Rounds number to the nearest representable value. If a tie occurs, rounds positive numbers toward positive infinity and rounds negative numbers toward negative infinity. Equivalent to the FixedPoint Designer
round
function.Simplest
Automatically chooses between round toward floor and round toward zero to generate rounding code that is as efficient as possible.
Zero
Rounds number toward zero. Equivalent to the MATLAB
fix
function.
Programmatic Use
Block Parameter:
RndMeth 
Type: character vector 
Values:
'Ceiling' 
'Convergent' 
'Floor' 
'Nearest' 
'Round' 
'Simplest' 
'Zero' 
Default:
'Floor' 
See Also
For more information, see Rounding (FixedPoint Designer).
Block Characteristics
Data Types 

Direct Feedthrough 

Multidimensional Signals 

VariableSize Signals 

ZeroCrossing Detection 

Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.
HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.
This block has one default HDL architecture.
ConstrainedOutputPipeline  Number of registers to place at
the outputs by moving existing delays within your design. Distributed
pipelining does not redistribute these registers. The default is

InputPipeline  Number of input pipeline stages
to insert in the generated code. Distributed pipelining and constrained
output pipelining can move these registers. The default is

OutputPipeline  Number of output pipeline stages
to insert in the generated code. Distributed pipelining and constrained
output pipelining can move these registers. The default is

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.
FixedPoint Conversion
Design and simulate fixedpoint systems using FixedPoint Designer™.
Version History
Introduced before R2006a
See Also
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