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EMS22 Output Waveforms

Quadrature: This output waveform is the

most common among all contacting and non-

contacting encoders. Quadrature, also known as

2-bit quadrature or incremental, is often used to

determine magnitude (count) and direction (up/

down) by an external interface circuit. EMS22

comes equipped with such capability; an external

interface circuit is not required. It also offers an

indexed output with an adjustable width of one or

three times the absolute position value that can be

used for counting the shaft rotation.

Direction/Step: This output is very similar to the

quadrature waveform but offers up to 512 PPR, as

opposed to 256 PPR in quadrature. This output can

be used in incremental counting applications where

a better resolution is desired. Indexing output is also

available with a Direction/Step output waveform.

Absolute: Absolute output refers to the absolute

angular position. This type of output is especially

useful for applications where the absolute position

of a device, such as a camera, is necessary to locate

an object. Also with 1024 distinct angular positions,

the EMS22 offers very high resolution indexing at

every 0.35 °. This type of output code is not affected

by a power outage to the encoder since each angular

position of the encoder has a unique code.

PWM: Pulse-Width Modulation is another form

of absolute waveform that utilizes the square wave

output generated by the sensor to control the

duty cycle of the output at different desired shaft

positions. The EMS22 encoder can generate pulse

widths as low as 1 µs, and as high as 1024 µs in a

complete signal period of 1025 µs. Some advantages

of using this output waveform over other output

types include immunity to noise and faster data

acquisition.

Figure 2: AS5040 ASSP in Two Different States

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