Allen-Bradley LOGIX 5000 Reference Manual page 345

Filter
WLead:WLag ratio
ZetaLead second order only
ZetaLag second order only
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.
Execution
Function Block
Condition/State Action Taken
Prescan EnableIn and EnableOut bits are cleared to false.
Tag.EnableIn is false EnableIn and EnableOut bits are cleared to false.
Tag.EnableIn is true EnableIn and EnableOut bits are set to true.
The instruction executes.
Instruction first run N/A
Instruction first scan Recalculate coefficients.
Postscan EnableIn and EnableOut bits are cleared to false.
Structured Text
Condition/State Action Taken
Prescan See Prescan in the Function Block table.
Normal Execution See Tag.EnableIn is true in the Function Block table.
Postscan See Postscan in the Function Block table.
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
If WLead > WLag, no limitations
If WLag > WLead:
• No minimum limitation for WLag:WLead
• First order maximum for WLag:WLead = 40:1 and the
instruction limits WLag to enforce this ratio
• Second order maximum for WLag:WLead = 10:1 and the
instruction limits WLag to enforce this ratio
LowLimit = 0.0
HighLimit = 4.0
LowLimit = 0.05
HighLimit = 4.0
Chapter 3
INF, the
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