Rockwell Automation 1769-IF16V Compact High Density Analog Input Modules - Manual (Page 43)

Publication 1769-UM018A-EN-P - October 2008 43
Module Data, Status, and Channel Configuration Chapter 3
Real Time Sampling
This parameter instructs the module how often to initiate a conversion
cycle that will convert each enabled input channel and then place that
data into the Input Data file. A conversion cycle is defined as the
sequential conversion of each input pair that has at least one of its
channels enabled. When the module has performed a conversion on
each of the input pairs, it is ready to begin the next conversion cycle.
This feature is applied on a module-wide basis.
During module configuration, you specify a Real Time Sampling (RTS)
period by entering a value into Word 0 of the Configuration Data file.
This value entered in Word 0 can be in the range of 0…5000 and
indicates the conversion cycle rate the module will use in 1 ms
increments.
If you enter a 0 for the Real Time Sample Rate, the modules initiate
conversion cycles at the fastest rate possible, controlled by the filter
setting selected for each enabled channel within the input pairs. Once
all of the channels’ input data has been converted, the Input Data file
is updated for all enabled channels at the same time.
If you enter a non-zero value for the Real Time Sample Rate, the
module compares the Real Time Sample Rate value with the
calculated module update time, again based on the filter setting
selected for each enabled channel within the input pairs. If the value
entered for the Real Time Sample Rate is smaller than the calculated
module update time, the module indicates a configuration error. The
longest Real Time Sample Rate supported by the modules is 5
seconds, which corresponds to the maximum value for Word 0 of the
Configuration Data file of 5000 decimal. See
Module Update Time and
Scanning Process on page 40 for details on calculating the module
update time.
Time Stamping
This parameter instructs the module to insert a time stamp value into
the Input Data file every time the file is updated.
During module configuration, you enable time stamping using Word
1, bit 15 of the Configuration Data file: Enable Time Stamping (ETS).
Setting the ETS bit (1) enables the module’s time stamping function.
Clearing the ETS bit (0) disables the function. The default condition of
the ETS bit is disabled (0).