User guide

Chapter 5: 1756sc-IF8H Channel Configuration, Data, and Status 41
Table 5.1d
Tag Name Data Type Style Description
If8h0Configuration.ModuleConfigBits.14
2
BOOL DEC Bits 14 and 15 determine how often
the pass-through command is serviced
by the module.
15,14 = 00 = pass-through serviced
once per two channels scanned
15,14 = 01 = pass-through serviced
once per module scan
15,14 = 1X = pass-through serviced
once per channel scan
If8h0Configuration.ModuleConfigBits.15
2
BOOL DEC Bits 14 and 15 determine how often
the pass-through command is serviced
by the module.
15,14 = 00 = pass-through serviced
once per two channels scanned
15,14 = 01 = pass-through serviced
once per module scan
15,14 = 1X = pass-through serviced
once per channel scan
2
The confi
g
uration of bits 14 and 15 directl
y
effect the update time of the HART data acquisition for the module, for example if
bit 15 is set, the HART update time for each channel w ill be doubled.
Module FilterModule Filter
Module FilterModule Filter
Module Filter
SelectionSelection
SelectionSelection
Selection
Module Update TimeModule Update Time
Module Update TimeModule Update Time
Module Update Time
The module update time is defined as the time required for the module to
sample and convert the input signals of all enabled input channels and
make the resulting data values available to the processor. The update time
is influenced by the input type and filter frequency configuration settings.
The following table shows associated time adders based on frequency
selection.
Filter Update Time
10Hz 61 ms per channel
15Hz 41 ms per channel
20Hz 31 ms per channel
50Hz 11 ms per channel
60Hz 11 ms per channel
100Hz 7 ms per channel
250Hz 3.5 ms per channel
1000Hz 2.25 ms per channel
ADC FilterADC Filter
ADC FilterADC Filter
ADC Filter
::
::
:
The module uses a ADC filter that provides high frequency noise rejection
for the input signals. The ADC filter is programmable, allowing you to
select from eight filter frequencies for each channel.