Rockwell Automation 1769-IR6 Compact I/O 1769-IR6 RTD/Resistance Input Module - Manual (Page 57)

Rockwell Automation Publication 1769-UM005B-EN-P - March 2012 57
Module Data, Status, and Channel Configuration Chapter 4
Engineering Units x 1 Data Format
If you select engineering units x 1 as the data format for an RTD input, the
module scales input data to the actual temperature values for the selected RTD
type per RTD standard. It expresses temperatures in 0.1
°C units. For
resistance inputs, the module expresses resistance in 0.1
Ω units, for all ranges
except the 150
Ω range. For the latter, resistance is expressed in 0.01 Ω units.
The resolution of the engineering units x 1 format is dependent on the range
selected and the filter selected. See Determining Effective Resolution and
Range on page 65.
Engineering Units x 10 Data Format
For the engineering units x 10 data format for an RTD input, the module
scales input data to the actual temperature values for the selected RTD type
per RTD standard. With this format, the module expresses temperatures in
1
°C units. For resistance inputs, the module expresses resistance in 1 Ω units,
for all ranges except the 150
Ω range. For the latter, resistance is expressed in
0.1
Ω units.
The resolution of the engineering units x 10 format is dependent on the range
selected and the filter selected. See Determining Effective Resolution and
Range on page 65.
Scaled-for-PID Data Format
If you select the scaled-for-PID data format, the module presents to the
controller a signed integer representing the input signal range proportional to
the selected input type. The integer value is the same for RTD and resistance
input types.
To obtain the value, the module scales the input signal range to a linearized
0…16383 range, which is standard to the PID algorithm for the MicroLogix,
SLC, and PLC controllers. The 0 value corresponds to the lowest temperature
or resistance value, while 16383 corresponds to the highest value. For example,
if a 100
Ω platinum 385 RTD is selected, the lowest temperature for the RTD,
-200
°C, corresponds to 0. The highest temperature, 850 °C, corresponds to
16383.
TIP Use the engineering units x 10 setting to produce
temperature readings in whole degrees Celsius or
Fahrenheit. See
Engineering Units x 10 Data Format
below.