Engineering Units X1; Engineering Units ×10; Scaled For Pid; Percent Range - Spectrum Controls 1769 Series User Manual

3-6 Chapter 3: Module, Data, Status, and Channel Configuration
NOTE
User's Manual Pub. 0300244-02 Rev. A
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 -32767 and +32767. For example, if a type J thermocouple is
selected, the lowest temperature of -210 °C corresponds to -32767 counts. The
highest temperature of 1200 °C corresponds to +32767.

Engineering Units x1

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.
Use the engineering units ×10 setting to produce temperature readings in
whole degrees Celsius or Fahrenheit.
Engineering Units ×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.

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 type J thermocouple is
used, the lowest temperature for the thermocouple is -210 °C, which corresponds
to 0 counts. The highest temperature in the input range, 1200 °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 type J thermocouple, the range -210 °C to +1200 °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
thermocouple or millivolt input device. Each channel can be individually
configured for any type of input.