Rockwell Automation 1769-IT6 Compact I/O 1769-IT6 Thermocouple/mV Input Module - Manual (Page 44)

44 Rockwell Automation Publication 1769-UM004B-EN-P - March 2010
Chapter 4 Module Data, Status, and Channel Configuration
Raw/Proportional Data
The value presented to the controller is proportional to the selected input and
scaled into the maximum data range allowed by the bit resolution of the A/D
converter and filter selected. The raw/proportional data format also provides the
best resolution of all the data formats.
If you select the raw/proportional data format for a channel, the data word will be
a number between -32,767 and 32,767. For example, if a type J thermocouple is
selected, the lowest temperature of -210 °C (-346 °F) corresponds to -32,767
counts. The highest temperature of 1200 °C (2192 °F) corresponds to 32,767.
See Determining Effective Resolution and Range on page 50.
Engineering Units x 1
When using this data format for a thermocouple or millivolt input, the module
scales the thermocouple or millivolt input data to the actual engineering values
for the selected millivolt input or thermocouple type. It expresses temperatures in
0.1 °C or 0.1 °F units. For millivolt inputs, the module expresses voltages in
0.01 mV units.
The resolution of the engineering units x 1 data format is dependent on the range
selected and the filter selected.
See Determining Effective Resolution and Range
on page 50.
Engineering Units x 10
When using a thermocouple input with this data format, the module scales the
input data to the actual temperature values for the selected thermocouple type.
With this format, the module expresses temperatures in 1 °C or 1 °F units.
For millivolt inputs, the module expresses voltages in 0.1 mV units.
The resolution of the engineering units x 10 data format is dependent on the
range selected and the filter selected.
See Determining Effective Resolution and
Range on page 50.
TIP The engineering units data formats represent real engineering
temperature units provided by the module to the controller. The
raw/proportional counts, scaled-for-PID, and percent of full-scale data
formats, may yield the highest effective resolutions, but may also require
that you convert channel data to real engineering units in your control
program.
TIP Use the engineering units x 10 setting to produce temperature readings
in whole degrees Celsius or Fahrenheit.