The 1771-ES PLC 5 Servo Encoder Feed-back Expander Module by Allen-Bradley is a component of the Servo Positioning Assembly which provides incremental digital encoder feedback, is located on the 1771 I/O chassis, and requires 2 slots. It has -+10V DC isolated maximum output voltage and uses a D/A Converter (DAC) with a 12-bit (signed) resolution. It also has a Drive Disable Output with 100mA source or sink current and 30V DC output voltage. The module draws a maximum backplane current of 1.7A and has encoder input voltage ratings of <1.6V DC (High) and >1V DC (Low). The 1mA sinking encoder input has a user-selectable encoder rates (Differential at 250 kHz max, Single Ended: 20 kHz max) selectable using a jumper selection which provides selection between the differential and single-ended options. The 1771-ES encoder has 3 programmable encoder multipliers (x1, x2, or x4), and its discrete input has 11.2k or 1.2k resistance selectable switch for each input. 

It has a Trachometer input with full-scale 3V (min) and 50V (max) and an input impedance of 20 Kilo Ohms. The 1771-ES has a maximum programmable position of +-999.9999 inches (res 0.0001 in), with a programmable speed range of 0.0001-9990 inches per minute (ipm) and a maximum Acceleration/Deceleration of 9999ipm/s. It has an initial gain of 0.01-9.99ipm/mil and a sample period time of 2.4ms. Keying on the left 1771 I/O chassis slot is achieved by attaching the connecting band between pins 2 and 4, 14 and 16, and on the right, the I/O chassis is between pins 4 and 6, 32 and 34. The 1771-ES’s operational temperature ranges between 32° and 140°F at 5-95% non-condensing relative humidity limits and is kept between 40 and 185°F when non-operational.