Allen-Bradley LOGIX 5000 Reference Manual page 396

Chapter 5 Statistical Instructions
396
Operands
Function Block
Operand Type
block tag MOVING_STD_DEV
StorageArray REAL
MOVING_STD_DEV Structure
Input Parameter Data Type
EnableIn BOOL
In REAL
InFault BOOL
Initialize BOOL
SampleEnable BOOL
NumberOfSamples DINT
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Format Description
structure MSTD structure
array Holds the In samples. This array
must be at least as large as
NumberOfSamples.
Description
Enable input. If cleared, the instruction does not
execute and outputs are not updated.
Default is set.
The analog signal input to the instruction.
Valid = any float
Default = 0.0
Bad health indicator for the input. If In is read
from an analog input, then InFault is normally
controlled by fault status on the analog input.
When set, InFault indicates the input signal has
an error, the instruction sets the appropriate bit in
Status, and the instruction holds Out and Average
at their current values. When InFault transitions
from set to cleared, the instruction initializes the
averaging algorithm and continues executing.
Default is cleared.
Initialize input to the instruction. When set, the
instruction sets Out = 0.0 and Average = In,
except when InFault is set, in which case, the
instruction holds both Out and Average at their
current values. When Initialize transitions from
set to cleared, the instruction initializes the
standard deviation algorithm and continues
executing.
Default is cleared.
Enable for taking a sample of In. When set, the
instruction enters the value of In into the storage
array and calculates a new Out and Average
value. When SampleEnable is cleared and
Initialize is cleared, the instruction holds Out and
Average at their current values.
Default is cleared.
The number of samples to be used in the
calculation. If this value is invalid, the instruction
sets the appropriate bit in Status and the
instruction holds Out and Average at their current
values. When NumberOfSamples becomes valid
again, the instruction initializes the standard
deviation algorithm and continues executing.
Valid = 1 to size of the storage array
Default = 1