Configuration of i.Board requires selecting one of two jumper positions for each input, and then selecting the corresponding input type in software via the web page. The voltage jumper position is used for voltage or 4-20mA input, or discrete input. The thermistor jumper position is used for thermistors, and also for dry contact input. The thermistor jumper applies a voltage to the input terminal via a pullup resistor. A contact closure to ground will produce a change of state when software is configured for dry contact input.

Configure an Analog Input for temperature by selecting the appropriate thermistor type. Configure 0-10V input by selecting 0-10V, and entering a slope and intercept that corresponds to your sensor. If using a 4-20mA sensor, you will need a dropping resistor connected in parallel across the sensor input. If you wish to use an input as a simple on/off input, select discrete or dry contact.

A calibration helper page is built in. Simply enter data from readings you have taken, or data from the sensor spec sheet, then enter the desired display range. The helper will calculate slope and intercept for you. It will even take resistor values into account when a dropping resistor is used. Simply click on the calibration helper link at the top of the Analog Inputs configuration page.

The difference between discrete and dry contact is this: With a discrete input, it is expecting you to provide external voltage excitation (up to 24VDC). With a dry contact input, it provides its own excitation, and you simply provide a contact closure to ground.

Discrete Outputs have an optional timer associated with them. The timer can do one of two things: (1) generate a pulsed output, or (2) impose a minimum on time qualification to prevent rapid cycling.