AX92352/AX92353 2-CH Encoder Card with Real-time Trigger I/O
Operating
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Section 4
Operating
4.1
Operating of AX92352
This section details the operations of the AX92352 2-CH Encoder Card with Real-time Trigger
I/O and how it works with the AX92353 4-CH LED lighting control module.
4.1.1
Encoder function
The AX92352 supports 2CH 32-bit incremental quadrature encoder input for the ABZ
signal in different modes, which is used for applications where direction sensing is
required. This mode consists of two square-wave pulse signals known as Phase A and
Phase B, which are generated by a rotating encoder. Phase A and Phase B signals are
coded 90° out of phase from each other: Phase A is either 90° phase leading or lagging
behind Phase B. The AX92352 supports 2CH 32-bit incremental quadrature encoder
input for the ABZ signal. It is able to count square-wave pulses of Phase A and Phase B,
and then determine the rotating direction of motor movement by comparing the phase
relationship between Phase A and B:
When the quadrature encoder is rotating in a clockwise direction, its signal will show
a positive direction of Phase A leading Phase B.
When the quadrature encoder rotates counterclockwise, its signal will show a
negative direction of Phase A lagging behind Phase B.
Besides direction, the quadrature encoder can generate another signal named Phase Z,
which is produced once per complete rotation of the quadrature encoder. Phase Z is
used by the AX92352 to locate a position of the motor when the quadrature encoder
completes a 360° rotation, so that the counter value of Phase Z can reset to zero if the
configuration sets the homing conditions.
Counter mode
x1 mode: The counter value will increment or decrement when a rising edge happens on
Phase A.
x2 mode: The counter value will increment or decrement when a rising edge or a falling
edge happens on Phase A.
x4 mode: The counter value will increment or decrement when a rising edge or a falling
edge happens on Phase A or B.
In most cases, the x4 Phase AB signal mode is applied to incremental encoder devices.
For example, when a motor completes a 360° rotation, an incremental encoder will
generate 1000 pulses per phase (A or B phase), but the count will show 4000 pulses.
1/2 mode: The counter value will increment or decrement when a rising edge happens
twice on phase A.
1/3 mode: The counter value will increment or decrement when a rising edge happens
three times on phase A.
1/4 mode: The counter value will increment or decrement when a rising edge happens
four times on phase A
