Engineering Units ×1; Engineering Units ×10; Scaled For Pid; Percent Range - Spectrum Controls 1769 User Manual

3-6 Chapter 3: Module, Data, Status, and Channel Configuration
NOTE
User's Manual Pub. 0300241-02 Rev. A
If you select the raw/proportional data format for a channel, the data word will be
a number between -32767 and +32767. For example, if a Pt 385 RTD is selected,
the lowest temperature of -200 °C corresponds to -32767 counts. The highest
temperature of 850 °C corresponds to +32767.
Engineering Units ×1
When using this data format for a RTD or resistance input, the module scales the
RTD or resistance input data to the actual engineering values for the selected
RTD or resistance input type. It expresses temperatures in 0.1 °C or 0.1 °F units
for RTDs. For resistance inputs, the module expresses resistance in 0.01Ω
increments.
Use the engineering units ×10 setting to produce temperature readings in
whole degrees Celsius or Fahrenheit.
Engineering Units ×10
When using a RTD input with this data format, the module scales the input data
to the actual temperature values for the selected RTD type. With this format, the
module expresses temperatures in 1 °C or 1 °F units. For resistance inputs, the
module expresses resistance in 0.1Ω increments.

Scaled for PID

The value presented to the controller is a signed integer with 0 representing the
lower input range and +16383 representing the upper input range.
To obtain the value, the module scales the input signal range to a 0 to +16383
range, which is standard to the PID algorithm for the MicroLogix 1500 and other
Allen-Bradley controllers (e.g. SLC). For example, if a Pt 385 RTD is used, the
lowest temperature for the RTD is -200 °C, which corresponds to 0 counts. The
highest temperature in the input range, 850 °C, corresponds to +16383 counts.

Percent Range

Input data is presented to the user as a percent of the specified range. The
module scales the input signal range to a 0 to +10000 range. For example, using
a Pt 385 RTD, the range -200 °C to +850 °C is represented as 0% to 100%.

3.2.5 Selecting Input Type (Bits 8 through 11)

Bits 8 through 11 in the channel configuration word indicate the type of RTD or
resistance input device. Each channel can be individually configured for any
type of input.

3.2.6 Selecting Temperature Units (Bit 7)

The module supports two different linearized/scaled ranges for RTDs, degrees
Celsius (°C) and degrees Fahrenheit (°F). Bit 7 is ignored for resistance input
types, or when raw/proportional, scaled-for-PID, or percent data formats are
used.