DRAND
Instances of function blocks are created according to
IEC61131-3, and then called, or otherwise accessed, from with the
PLC program using the instance names.
The function block permits generation of a (pseudo-) random number
of type LREAL.
VAR_INPUT
VAR_INPUT
Seed : INT;
END_VAR
Seed : Initial value for specification of the random number series.
VAR_OUTPUT
VAR_OUTPUT
Num : LREAL;
END_VAR
Num : This output returns a pseudo-random number in the range 0.0 .. 1.0 with double accuracy. The generator here creates a number series with 1075 stochastic values per period.
Example of calling the block in FBD:
In the example the LREAL value 0.643412 is generated and returned. The input parameter ”Seed" affects the initial value of the series. If, for instance, a deterministically reproducible random number series is desired in different sessions, and identical ”Seed" value must be used.
Requirements
|
Development environment |
Target system type |
PLC libraries to include |
|---|---|---|
|
TwinCAT v2.7.0 |
PC or CX (x86) |
PLCSystem.Lib |
|
TwinCAT v2.8.0 |
PC or CX (x86) |
TcSystem.Lib |
|
TwinCAT v2.10.0 Build >= 1301 |
CX (ARM) |
TcSystem.Lib |