Publication 1769-UM005A-EN-P
4-26
Module Data, Status, and Channel Configuration
Determining 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
provide the resulting data values to the processor. The module
sequentially samples the channels in a continuous loop as shown below.
Module Update Sequence
Module update time is dependent on the number of input channels
enabled, input filter selection, and whether or not a calibration or lead
wire compensation sequence is in progress.
The fastest module update time occurs when only one channel is enabled
with a 1 kHz filter, with autocalibration and cyclic lead compensation
disabled. If more than one channel is enabled, the update time is faster if
all channels use the fastest filter, as shown in example 1 below. The
slowest module update time occurs when all six channels are enabled
with the 10Hz filter.
The following table shows the channel update times for all filter
frequencies assuming that no calibration or lead wire compensation is in
progress.
.
Module update time can be calculated by obtaining the sum of all enabled
channel update times. Channel update times include channel scan time,
channel switching time, and reconfiguration time.
Channel 0 Disabled
Channel 1 Disabled
Channel 2 Disabled
Channel 5 Disabled
Sample
Channel 0
Sample
Channel 1
Sample
Channel 2
Sample
Channel 5
Enabled
Enabled
Enabled
Enabled
Channel X Autocalibration or Lead Wire Compensation Disabled
Channel X Autocalibration or Lead Wire Compensation
Table 4.15 Channel Update Time vs. Filter Frequency
Filter Frequency
Maximum Channel Update Time
(1)
(1) Update times do not include cyclic calibration or lead wire compensation.
with 1 channel enabled
with 6 channels enabled
10 Hz
303 ms
1818 ms
50 Hz
63 ms
378 ms
60 Hz
53 ms
318 ms
250 Hz
15 ms
90 ms
500 Hz
9 ms
54 ms
1 kHz
6 ms
36 ms
EXAMPLE
1.
Module Update Time with all channels enabled and
configured with 10Hz filter = 6 x 303 ms = 1818 ms
2.
Module Update Time with all channels enabled and
using the 1 kHz filter = 6 x 6 ms = 36 ms
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