IDEC MICROSmart FC6A Series Ladder Programming Manual page 548

27: F C
LOW ALCULATION
Dead Band Function
The dead band function filters minute changes in the value input to the SCALE instruction.
The SCALE instruction always retains the following two values.
Output value:
Output value (dead band): The result of filtering the input value with the dead band
The fluctuation range to perform filtering is set as the dead band.
If the fluctuation range of the output value is smaller than the dead band, the output value (dead band) is not updated.
Output value
When the SCALE instruction is executed, it stores the value scaled in the first scan in output value (D1+0, D1+1) and updates the
output value (dead band) (D1+2, D1+3).
The operation at this time differs according to whether or not the dead band is enabled.
When the dead band is enabled
The output value (D1+0, D1+1) and the output value (dead band) (D1+2, D1+3) are compared, and the value is stored
depending on which of the absolute value of that difference (D1+4, D1+5) and the size of the dead band (S2+6, S2+7) are larger.
• If the absolute value of the difference (D1+4, D1+5) between the output value (D1+0, D1+1) and the output value (dead band)
(D1+2, D1+3) is less than the dead band (S2+6, S2+7)
The output value (D1+0, D1+1) is not stored in the output value (dead band) (D1+2, D1+3).
• If the absolute value of the difference (D1+4, D1+5) between the output value (D1+0, D1+1) and the output value (dead band)
(D1+2, D1+3) is greater than or equal to the dead band (S2+6, S2+7)
The output value (D1+0, D1+1) is stored in the output value (dead band) (D1+2, D1+3) and output value (dead band) change
notification (D2+0) turns on for one scan.
If the dead band is disabled (dead band (S2+6, S2+7)=0)
The output value (D1+0, D1+1) is stored in the output value (dead band) (D1+2, D1+3) with each scan.
27-2
I
NSTRUCTIONS
The result of scaling the input value with each scan
Output value (dead band)
Dead band
FC6A S MICROS
ERIES MART
L P M
ADDER ROGRAMMING ANUAL
FC9Y-B1726