Spectrum Controls 2085sc-IF8U User Manual page 40

3-16 Chapter 3: Configuring the 2085sc-IF8u Using CCW
ADC MUX/PGA
Filter Settling
Selection Time
17 Hz 10
4 Hz 10
62 Hz 10
470 Hz 10
User's Manual Pub. 0300305-01 Rev. A
Input ADC Filter Frequencies Description
The modules use an input ADC digital filter that provides high-frequency noise
rejection for each input signal. The filter setting attenuates the input signal
beginning at the specified frequency. The filter for each channel is
programmable, allowing you to select from four different filter frequencies.
Index Filter (Hz)
0
1
2
3
The software uses the following channel scan times. The scan time is based on
each channel's Input ADC Filter configuration, and is the sum of the multiplexer
settling time, PGA register setup time, ADC conversion period (which is
[2/filter] + 1 ms), and microcontroller processing overhead.
With controllable channel-timer setup for detecting and open-circuit condition or
measuring lead-wire resistance, each channel is able to perform 2 measurements
to achieve user-defined requirements. By setting up different timer periods, you
can vary the channel scan rate. Below is the approximate timing for each input
filter selection:
ADC MCU
Conversion Processing
Time Overhead
121 8
481 8
33 8
5 8
 All timing units are in ms.
NOTE
 *: Channel configuration setup for 1 measurement only. This
applies to all measurements.
 **: Channel configuration setup for 2 measurements. This
applies to V/mV/TC measurements. The second measurement
happens every 3 seconds. The result is averaged.
 ***: Channel configuration setup for 2 measurements on
RTD/R with 3-wire compensation. The second measurement
happens every 60 seconds. The result is averaged.
Note
17 Default
4
62
470
Total Channel Scan Rate
Measurement per Channel
II,
I*
V/mV/TC**
139 141
499 501
51 53
23 25
II,
RTD/R***
140
500
52
24