2. Specifications
2.4. Functions
40
Analog Input Module 2MLF-AV8A, AC8A User's Guide
R200
Honeywell
September 2010
Sampling process
It collects analog input signal through general A/D conversion processing at specific
interval of time. The time required for A/D conversion of analog input signal depends on
the number of channels used.
(Processing time) = (Number of Channels used) X (Conversion speed)
Example:
If the number of channels used is 3, its process time is
=
(3) X (250µs) = 750μs
Sampling is performed to calculate the value of continuous analog signal at a specific
interval.
Filter process
Filter process function is used for obtaining stable digital output value by filtering noise
or sudden change in input value. Filter constant can be specified for respective channels
through user program or I/O parameters setting.
Setting range: 1 ~ 99 (%)
F[n] = (1 -
α) x A[n] + α x F [n
- 1]
F[n]: Current filter output value
A[n]: Current A/D conversion value
F[n-1]: Previous filter output value
α: Filter constant (0.01 ~ 0.99:
previous value added)
1.
If the filter setting value is not specified within 1 ~ 99, RUN LED blinks at an
interval of 1s. In order to set RUN LED to ON status, set the filter setting value
within 1 ~ 99. Then change PLC CPU mode from STOP to RUN. Ensure to clear
the request flag (UXY.11.0) from online modification (in RUN mode).
