Specifications

8-158 | OWNER’S GUIDE
Motion Encoders
Motion encoders have usually three channels: channel A, B and Z. Channel A and channel B provide the
square signals for the counter, and have a phase shift of 90°. From this phase shift the decoder is able to
recognize the rotation direction of the motion encoder. The third channel outputs one pulse at a certain
position at each revolution. This pulse is used to set the counter to zero. The number of counts per cycle at
a given motion encoder depends on the type of decoding: X1, X2, or X4. Some motion encoders have two
outputs, which work in a different way. Either channel A or channel B provides the square signal, depending
on the direction of the rotation.
The next sections illustrate the basic encoder modes that are supported:
Quadrature Encoder
In the rst case, X1 decoding is explained. When Input A leads Input B in a quadrature cycle, the counter
increments on rising edges of Input A. When Input B leads Input A in a quadrature cycle, the counter decre-
ments on the falling edges of Input A. At every Sample Clock ((1), (2), ... (9)) the counter value is read out.
Quadrature Encoder X1 Mode gure: