Spectrum Controls 1746sc-NI8u - Manual (Page 42)

30 SLC 500 ™ Universal Analog Input Module
Note: On alternate module scans, the 314 msec lead resistance sampling
time would be replaced by a 64 msec CJC sampling time.
Update Time Calculation Example
The following example shows how to calculate the module update
time for the given configuration:
Channel 0 configured for mV input at 250 Hz filter frequency, enabled
Channel 1 configured for mV input at 250 Hz filter frequency, enabled
Channel 2 configured for mV input at 50 Hz filter frequency, enabled
Channel 3 disabled
Channel 4 configured for RTD input at 50Hz filter frequency, enabled
Channel 5 through 7 disabled
Using the values from the table above, add the sum of all enabled channel
sample times, plus one 50 Hz lead resistance update time.
Channel 0 sampling time = 26 msec
Channel 1 sampling time = 26 msec
Channel 2 sampling time = 74 msec
Channel 4 sampling time = 74 msec
Lead Resistance
Sampling time
= 74 msec
Module update time = 274 msec
Channel Turn-On,
Turn-Off, and
Reconfiguration
Times The time required for the module to recognize a new configuration
for a channel is generally one module update time plus 1.865 msec
per newly configured channel. If the filter frequency selected for the
newly enabled, configured channel is new to the module, then auto-
calibration will be performed following configuration recognition.
Turn-off time requires up to one module update time.
Reconfiguration time is the same as turn-on time.
Auto-Calibration
Auto-calibration is performed by the module to correct for drift errors
over temperature. Auto-calibration occurs immediately following
configuration of a previously unselected filter frequency for the
particular input path. If all enabled channels have the calibration
disable configuration bit set to zero, auto-calibration also occurs as a
continuous cycle, where every two minutes all the required filter
frequencies and input paths are calibrated. There are three input paths in
the system to accommodate all the input options: a low voltage input path,