Rockwell Automation 1769-IF4FXOF2F Compact Combination Fast Analog I/O Module - Manual (Page 47)

Publication 1769-UM019A-EN-P - October 2008 47
Module Data, Status, and Channel Configuration Chapter 3
If you enter a zero for the Real Time Sample Rate, the module initiates
conversion cycles at the fastest rate possible, controlled by the filter
setting selected for each enabled channel. Once all of the channels’
input data have 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 minimum
and maximum values allowed by the module. If the value entered for
the Real Time Sample Rate is less than 0 or greater than 5000 decimal,
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.
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 by using
Word 1, bit 15 of the Configuration Data file: Enable Time Stamping
(ETS). Setting the ETS bit (ETS = 1) enables the module’s time
stamping function. Clearing the ETS bit (ETS = 0) disables the
function. The default condition of the ETS bit is disabled (ETS = 0).
When time stamping is enabled, the module provides a rolling time
stamp value of 0…32,767 with each count representing 1 ms. When
the time stamp count reaches 32,767, the value is reset to 0 and
continues to increment 1 count every millisecond.
When enabled, the Input Data file is updated with the latest time
stamp value that corresponds to the end of each module conversion
cycle. Sequentially, each enabled input is converted once per
conversion cycle. When Real Time Sampling is not enabled,
conversion cycles are repeatedly initiated at the module update rate. If
Real Time Sampling is used, the conversion cycles are initiated at a
rate equal to the real-time sampling rate. The time stamp value is
updated at the end of every conversion cycle.