OPTEK reserves the right to make changes at any time in order to improve design and to supply the best product possible.
Incremental Shaft Encoder
OPE1275S Single Channel (Tachometer)
OPE2275S Dual Channel
OPTEK Technology Inc. — 1645 Wallace Drive, Carrollton, Texas 75006
Phone: (972) 323-2200 or (800) 341-4747 FAX: (972) 323-2396 sensors@optekinc.com www.optekinc.com
Issue A 10/09
Page 4 of 4
Timing Definitions:
PPR = Pulses Per Revolution
Electrical Degree (°e) = 1/360th of 1 cycle
Cycle = 360 electrical degrees (°e)
Symmetry = Relationship between X & Y in electrical
degrees (°e).
Position Error = The difference between the actual
shaft position and the position indicated by
the encoder cycle count.
Quadrature: The lead or lag difference between
channels “A” and “B” in electrical degrees
(normally 90°e)
Cycle Error = The difference between the actual shaft
rotational position and the cycle count
rotational position.
Rise Time = Time required to switch between 10% and
90% of the highest to lowest signal levels.
Fall Time = Time required to switch between 90% and
10% of the highest to lowest signal levels.
Timing Diagram:
