Allen-Bradley LOGIX 5000 Reference Manual page 327

Filter
Description
The HPF instruction uses the Order parameter to control the sharpness of the
cutoff. The HPF instruction is designed to execute in a task where the scan rate
remains constant.
The HPF instruction uses these equations:
When:
Order = 1
Order = 2
Order = 3
with these parameter limits (where DeltaT is in seconds):
Parameter
WLead first order
LowLimit
WLead second order
LowLimit
WLead third order
LowLimit
HighLimit
Whenever the value computed for the output is invalid, NAN, or
instruction sets Out = the invalid value. When the value computed for the output
becomes valid, the instruction initializes the internal parameters and sets Out =
In.
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See Common Attributes for operand-related
faults.
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
The instruction uses this transfer function:
Limitations
Chapter 3
INF, the
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