Allen-Bradley 1794-IRT8 - System Throughput and Data Mapping

Publication 1794-6.5.12 - November 1997
How Communication Takes Place and I/O Image Table Mapping with the DeviceNet Adapter 5-3
System Throughput System throughput, from analog input to backplane, is a function of:
• the data format selected
• the type and mode of sensors selected
• whether filtering is selected
The A/D converter which converts channel 0 through 7 analog data to a
digital word provides a programmable single low pass filter. You can set
the frequency of this filter during module configuration. The selection
influences the A/D output data rate, thus affecting system throughput.
Mapping Data into the
Image Table
FLEX I/O Thermocouple/RTD input module data table mapping is shown
below.
Thermocouple/RTD Input Module (1794-IRT8) Image Table
Mapping
Module Image
I/O Image
Input Data Channel 0
Input Data Channel 1
Input Data Channel 2
Input Data Channel 3
Input Data Channel 4
Input Data Channel 5
Input Data Channel 6
Input Data Channel 7
Underrange
Input Size
Output Size
0 to 4 Words
1 to 11 Words
Overrange
DiagnosticsCJCAlarms
EDT command and responseRFlg
EDT command and dataCFlg
RTD Offsets for each channel
Sensor TypeSensor TypeMode Mode
TC/RTDTC/RTD
Filter CutReference Jct
Data Format
FM