The analog input section applies to the A/UI inputs, which are analog/universal inputs. These inputs may be configured for voltage, thermistor, discrete or dry contact. They may also be configured for 0-20mA or 4-20mA with an external resistor.

These physical inputs correspond to BACnet AI objects starting at #1.

Device Model: Use this to select which type of device you are configuring. Selecting the correct type renumbers the objects on the screen and also makes sure you are attempting to communicate with the correct objects in the device. This selection is shown here with AI objects, but is simply at the top of the screen, and applies to the entire device.

Type: Select analog, fast analog, discrete, or dry contact. Where both analog and fast analog appear, you have a choice between high resolution and standard resolution. High resolution is 15-bit data but scan time is slow (7 seconds for all 18 channels on AddMe III). Standard resolution is 10-bit data, and is the only resolution available on AddMe Lite (and appears simply as Analog on the list).

The only difference between discrete and dry contact is whether excitation is provided by AddMe. Discrete expects external excitation. Dry contact applies 5V @ 1mA (approx) to the input. In either case, a simple threshold test is made, and the threshold setting in percent determines when the input is regarded as on and off.

Scaling: Select 0-10V or a thermistor type for analog inputs. When thermistor is selected, internal excitation is applied to the input and a 58 point linearization table is automatically applied to derive temperature from the input data. When input type is discrete or dry contact, the selections are normal or inverted. In "normal" mode, the state will be binary one when input voltage is above the threshold, and zero below the threshold. The reverse is true when "inverted" is selected. When configured as dry contact input, select "inverted" to cause a contact closure to ground to generate a binary one.

Slope: Slope and intercept are applied to raw data from the integer register assigned to the input to derive the values that are placed in the corresponding floating point register. This allows conversion to virtually any engineering units.

Intercept: See slope comment above. Note that a sensor calibration tool is provided here to calculate slope and intercept given input voltage or current and expected scaled data readings.

Thres/Filter: Enter a threshold in percent of scale to determine on and off for discrete or dry contact inputs. Set to non-zero to enable analog filtering when an analog input type is selected.

A/UI#: Enter a number or use up/down arrows to scroll through the available analog input objects.