Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 70)

70 Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
Chapter 5 1756-IF16H HART Analog Input Module
Real Time Sampling (RTS)
This parameter instructs the module how often to scan its input channels and
obtain all available data. After the channels are scanned, the module multicasts
that data. This feature is applied on a module-wide basis.
During module configuration, you specify a real time sampling (RTS) period and
a requested packet interval (RPI) period. Both of these features instruct the
module to multicast data, but only the RTS feature instructs the module to scan
its channels before multicasting.
Underrange and Overrange Detection
The module detects when it is operating beyond limits of the input range. This
status indication tells you that the input signal is not being measured accurately
because the signal is beyond the measuring capability of the module. For example,
the module cannot distinguish between 20.5 mA and 22 mA
The following table shows the input ranges of the 1756-IF16H module and the
lowest and highest signal available in each range before the module detects an
underrange and overrange condition.
Table 11 - Low and High Signal Limits on the 1756-IF16H Module
Module Available Range Lowest Signal in
Range Highest Signal in
Range
1756-IF16H 0…20 mA
4…20 mA 0 mA
3.42 mA 20.58 mA
20.58 mA