Rockwell Automation 1769-IR6 Compact I/O 1769-IR6 RTD/Resistance Input Module - Manual (Page 59)

Rockwell Automation Publication 1769-UM005B-EN-P - March 2012 59
Module Data, Status, and Channel Configuration Chapter 4
Percent of Full Scale Data Format
With the percent of full scale data format, the module presents input data to
the user as a percent of the user-specified range. For example, for a 100
Ω
platinum 385 RTD, the range -200 °C…850 °C is represented as 0 percent to
100 percent. See Determining Effective Resolution and Range on page 65.
Selecting Input/Sensor Type (Bits 8…11)
You can set bits 8…11 in the channel configuration word to indicate the type
of input sensor, for example, 100
Ω platinum 385 RTD. Each channel can be
configured for any input type. The valid input types and bit settings are listed
in the channel configuration table on page 4-51.
Selecting Temperature Units/Mode (Bit 7)
The module supports two different linearized, scaled temperature ranges for
RTDs, degrees Celsius (°C) and degrees Fahrenheit (°F). You can select the
type that is appropriate for your application by setting bit 7 in the channel
configuration word. Bit 7 is ignored for resistance input types or when raw/
proportional, scaled-for-PID, or percent data formats are used.
Selecting Open-Circuit Response (Bits 5 and 6)
Broken inputs for the module include open-circuit and short-circuit
conditions. An open-circuit occurs when the module’s maximum input voltage
is reached. This can happen if the wire is cut or disconnected from the
terminal block. The module can encounter an open-circuit for any RTD or
resistance input.
A short-circuit occurs when the calculated lead wire compensated resistance is
less than 3
Ω. The module can only report a short-circuit for an RTD.
Use bits 5 and 6 of channel configuration word 6 to define the state of the
channel data word when a broken input condition is detected for the