Spectrum Controls 140 AUI 040 00sc - Manual (Page 14)

16-Channel Universal Analog Input Module
15
Selecting an autocalibration schedule rate is an exercise in tradeoffs. Performing autocalibration more fre-
quently may result in greater accuracy due to variations caused by environmental factors such as temperature.
This accuracy has a cost in the burden imposed by performing the calibration. The calibration time is a
function of the filter frequency. Calibration times are listed below. The system cannot update the channel
data while performing calibration. In addition, if multiple filter frequencies are selected, calibrations for each
frequency and the execution time is cumulative. The worst case calibration time is when all filter frequencies
are enabled (7.8, 13.6, 50/60 and 1677 Hz). The time is then the total for all four times listed below. Also,
note that the channel enables have no effect on the auto calibration feature. If a filter frequency is enabled via
the zoom screens, then the autocalibration is performed for the frequency.
Filter Freq. 16 Ch. Update Rate
7.8 Hz - 3db 1992 msec
13.6 Hz - 3bd 1168 msec
209.6 Hz - 3db 132 msec
1677 Hz - 3db
80 msec
2.5 4X Register Configuration
Refer to Chapter 4 for 4x register setting information.