Campbell Scientific CR9000X Measurement and Control System - Manual (Page 268)

Section 7. Measurement Instructions
7-44
The filter module collects alias-free, 50-kHz samples from each of its six
analog-to-digital converters; applies additional real-time, finite-impulse-
response filtering, and decimates (down samples) the 50-kHz data to the
programmed scan rate. The Filter Module supports 726 different scan intervals
including the basic ones shown in the table below. For scan intervals not
listed, enter the scan interval desired, download the program, and the logger
will return suggested operational scan intervals close to the one that was
entered.
See Appendix B for a list of all available scan intervals.
Scan Interval Scan Rate
20 μs 50 kHz
40 μs 25 kHz
100 μs 10 kHz
200 μs 5 kHz
400 μs 2.5 kHz
1 ms 1000 Hz
2 ms 500 Hz
4 ms 250 Hz
10 ms 100 Hz
20 ms 50 Hz
40 ms 25 Hz
100 ms 10 Hz
200 ms 5 Hz
VoltFilt (Dest, Reps, Range, FSlot, Chan, FiltOption, Excitation, Mult,
Offset)
The VoltFilt instruction is used to obtain voltage measurements from the
CR9052 Filter Module in much the same way as the VoltDiff instruction is
used with the CR9050 module. The program scan interval (or the SubScan
Interval: see the SubScan topic in Section 9.1 Program Structure/Control)
determines the filter module output interval. Data are passed from the Filter
Module to the CR9000X CPU for processing and final storage at this scan
interval. There is the option of turning on a fixed excitation. No ratiometric
scaling (as in the bridge measurement instructions) is applied when the
excitation is on; the VoltFilt instruction always returns millivolts scaled by the
multiplier and offset.
This instruction must NOT be placed inside a conditional
statement or Slow Sequence Scan. NOTE