Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 46)

Publication 1746-UM022B-EN-P - January 2005
4-6 Channel Configuration, Data, and Status
The proportional counts are scaled to fit the defined temperature or
voltage range. The input signal range is proportional to your selected
input and scaled into a -32,768 to 32,767 range.
Using Scaled-for-PID and Proportional Counts
The thermocouple module provides eight options for displaying input
channel data. These are 0.1°F, 0.1°C, 1°F, 1°C, 0.01 mV, 0.1 mV,
Scaled-for-PID, and Proportional Counts. The first six options
represent real Engineering Units displayed by the 1746-NT8 and do
not require explanation. The Scaled-for-PID and Proportional Counts
selections provide the highest NT8 display resolution, but also require
you to manually convert the channel data to real Engineering Units.
The equations below show how to convert from Scaled-for-PID to
Engineering Units, Engineering Units to Scaled-for-PID, Proportional
Counts to Engineering Units, and Engineering Units to Proportional
Counts. To perform the conversions, use the defined temperature or
millivolt range for the channel’s input type. See the Channel Data
Word Format table on page 4-8. The lowest possible value for an
input type is S
LOW
, and the highest possible value is S
HIGH
.
Effective Resolutions
The effective resolution for an input channel depends upon the filter
frequency selected for that channel.