- 2048 PPR Optical Incremental Rotary Encoder - 10mm Diameter Hollow Shaft and Face MountPart No: DRO-AT-O50-H10-2048-T33T£175.10A 2048 Pulses Per Revolution (PPR) incremental rotary encoder, optical sensing type. With 10mm diameter hollow shaft. The encoder can be mounted by the M4 threaded holes in the front face. 50mm diameter housing with side cable exit. Industrial standard quadrature TTL output. Also known as a hollow shaft encoder. Learn More