The Allen-Bradley 931S-P491 smart programmable signal converter is a signal conditioner with an interactive display that is designed to improve the signal quality from field devices to a controller or a control system. This device, like every other device in the Bulletin 931S series, utilizes the principle of transformer coupling to galvanically isolate, reproduce, and transmit signals from a field device to a control system. Unlike other signal conditioners in its series, the 931S-P491 signal conditioner offers a universal power supply to accommodate a wide range of applications, and it is designed to accept a wide range of input signals. It comes with an interactive, on-board display panel with 3 front-panel pushbuttons for easy and simplified configuration, and it also has a DIP switch for additional control.

The 931S-P491 signal conditioner requires 24 to 230 Volts DC or 24 to 230 Volts AC (at 48 to 62 Hertz) of voltage range for operation, and it has a maximum power consumption rating of 2.3 Watts. It has 1 passive input channel with a configurable input current signal range of ± 0.1 milliamps to ±100 milliamps and a configurable input voltage signal range of ±20 millivolts to ±300 Volts. It also has an input current resistance rating of 100 Ohms and a voltage resistance rating of 1 megaohm. The 931S-P491 signal conditioner has a single active/passive output channel that provides standard analog output signals, and it offers 3-way galvanic isolation between the device input, output, and auxiliary power supply. The 931S-P491 signal conditioner has an isolation voltage rating of 4 kilovolts, and rated impulse withstand voltage of 5 kilovolts. The 931S-P491 signal conditioner has an average shipping weight of 130 grams and approximate dimensions of 12.5 x 116.2 x 113.6 millimeters.