Rockwell Automation 1769-OF4VI Compact I/O Isolated Analog Modules - Manual (Page 50)

Publication 1769-UM014B-EN-P - May 2010
3-12 Module Data, Status, and Channel Configuration for the Input Module
The module compares the Real Time Sample Rate value entered in Word 0 of
the Configuration Data file with each input channel’s calculated update time,
again based on the filter setting selected for each enabled channel. If the value
entered for the Real Time Sample Rate is smaller than any input channel’s
calculated update time, the module indicates a configuration error. The longest
Real Time Sample Rate supported by the 1769-IF4I is 5s, the maximum value
for Word 0 of the Configuration Data file is 5000 decimal.
1769-IF4I 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).
The 1769-IF4I provides (when enabled) a rolling time stamp value of 0 to
+32767 with each count representing 1 ms. When the time stamp count
reached +32767, the value is reset to 0 and the value continues to increment
one count every ms.
When enabled, the time stamp value in the Input Data file is updated with the
current time stamp value each time an input channel data value is updated by
the module. In normal sampling mode, each input channel of the 1769-IF4I is
sampled and its converted value is placed into the Input Data file at a rate set
by the filter setting for the channel.
Since each input channel is sampled independent from the other input
channels, the time stamp value is updated each time any channel’s value is
updated. If Real Time Sampling is used, the values of all enabled input
channels are updated in the Input Data file at the same time. In this case, the
time stamp value is updated once per Real Time Sample period at the same
time the channels’ data values are updated.