Have a combination of analog inputs to measure process sensors such as pressure transducers and temperature sensors, analog outputs for proportional control and digital I/O and counter/timer channels for on/off pulses.
Generate analog output signals in the ranges of 0 to 10V, +-5V or 4 to 20 mA. These signals are typically used for controlling other devices such as valves, dampers and speed controllers.
Accept discrete or digital signals rather than analog signals. Digital Inputs record the on/off status of a field device. Digital Outputs are used to turn external devices on or off. Counters measure the number of accumulated on/off pulses.
Communications boards plug directly into the computer bus and add RS-232, RS-422 or RS-485 communications capability to a computer. Single, dual, four or eight port cards are available.
