A-B Rockwell Automation 847H-DN1A-RG00500. Incremental Encoder, 2.5" Diameter, Solid Shaft, Standard Square Flange, 3/8 Diameter Shaft with Flat, 4.5 5.5 V DC, 4.5 5.5 V Line Driver (TTL), Radial Exit, MS 10 Pin w/ Mating Connector, B leads A, CW, Z gated with BN, 500 PPR