An internal, high gain, fully-differential amplifier and a 16-bit analog-to-digital converter combine to accurately digitize the input signal. The analog input is digitally filtered, to user selected sample size and filter window (band), allowing optimization for specific operating conditions, trading off depth of filtering and step change tracking. Self-calibrating +/- 10Vdc and 4-20mA analog output signals are standard. A RS232 interface provides facilities to communicate, command, query operating modes, parameters and to continuously read data.