DL06 Micro PLC User Manual, 3rd Edition, Rev. E
5-240
Chapter 5: Standard RLL Instructions
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Filter Over Time - BCD (FILTER) (IB-422)
Filter Over Time BCD will perform a first-order filter on the Raw Data on a defined time
interval. The equation is:
New = Old + [(Raw - Old) / FDC]
where,
New: New Filtered Value
Old: Old Filtered Value
FDC: Filter Divisor Constant
Raw: Raw Data
The Filter Divisor Constant is an integer in the range K1 to K100, such that if it equaled K1
then no filtering would be done.
The rate at which the calculation is performed is specified by time in hundredths of a
second (0.01 seconds) as the Filter Freq Time parameter. Note that this Timer instruction is
embedded in the IBox and must NOT be used anywhere else in your program. Power flow
controls whether the calculation is enabled. If it is disabled, the Filter Value is not updated.
On the first scan from Program to Run mode, the Filter Value is initialized to 0 to give the
calculation a consistent starting point.
FILTER Parameters
• Filter Frequency Timer: specifies the Timer (T) number which is used by the Filter instruction
• Filter Frequency Time (0.01sec): specifies the rate at which the calculation is performed
• Raw Data (BCD): specifies the V-memory location of the raw unfiltered BCD value
• Filter Divisor (1-100): this constant used to control the filtering effect. A larger value will increase
the smoothing effect of the filter. A value of 1 results with no filtering.
• Filtered Value (BCD): specifies the V-memory location where the filtered BCD value will be placed
DS
Used
HPP
N/A
Parameter
DL06 Range
Filter Frequency Timer
T
T0-377
Filter Frequency Time (0.01 sec)
K
K0-9999
Raw Data (BCD)
V
See DL06 V-memory map - Data Words
Filter Divisor (1-100)
K
K1-100
Filtered Value (BCD)
V
See DL06 V-memory map - Data Words
