Rockwell Automation 1746-NI8 SLC 500 Analog Input Modules User Manual - Manual (Page 46)

5–5 Channel Configuration, Data, and Status
Publication 1746Ć6.8 - April 1997
While the channel enable bit is cleared (0), the channel data word
and status word values are cleared. After the channel enable bit is
set, the channel data word and status word remain cleared until the
module sets the channel status bit (bit 11) in the channel status word.
(Refer to Channel Status on page
5–11.)
Unused Bits (Bits 12-15)
Bits 12–15 are not defined. Ensure these bits are always set to zero.
The module input image uses 8 data word values whether the module
is in Class 1 or Class 3 mode. The converted voltage or current input
data values reside in I:e.0 through I:e.7 of the module’s input image
file. When an input channel is disabled, its data word is reset to
zero.
1746ĆNI8 Module Input Image - Data Word
Class 1 Class 3
I:e.0 channel 0 data word 16 bit integer • •
I:e.1 channel 1 data word 16 bit integer • •
I:e.2 channel 2 data word 16 bit integer • •
I:e.3 channel 3 data word 16 bit integer • •
I:e.4 channel 4 data word 16 bit integer • •
I:e.5 channel 5 data word 16 bit integer • •
I:e.6 channel 6 data word 16 bit integer • •
I:e.7 channel 7 data word 16 bit integer • •
The channel data word contains a 16-bit integer that represents the
value of the analog input channel. The tables below show the
channel data word values for various input types and data formats.
The second table shows the default full-scale values for the
proportional counts data format. The table does not imply the entire
data value range is usable resolution.
Channel Data Word Values for Engineering Units
Input Type Signal Range Engineering Units Engineering Units Scale
± 10V dc -10.25V to +10.25V -10250 to +10250 1mV/step
0-5V dc -0.5V to +5.5V -500 to +5500 1mV/step
1-5V dc +0.5V to +5.5V +500 to +5500 1mV/step
0-10V dc -0.5V to +10.25V -500 to +10250 1mV/step
0-20 mA -0.5 mA to 20.5 mA -500 to 20500 1.0uA/step
4-20 mA 3.5 mA to 20.5 mA 3500 to 20500 1.0uA/step
± 20 mA -20.5 mA to 20.5 mA -20500 to 20500 1.0uA/step
0-1 mA -0.05 mA to 1.05 mA -50 to 1050 1.0uA/step
Channel Data Word