750-634 [Incremental Encoder Interface]
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11
Functional
Description
WAGO-I/O-SYSTEM 750
I/O Modules
2.1.1.6 Functional
Description
Typically, incremental encoders supply two output signals for the encoder
track, both 90° offset. These signals are designated A and B.
Usually, incremental encoders have an index track in addition to the two track
signals. This index track only produces one pulse per one full encoder
revolution. This pulse and the counter reading can be used to determine the
absolute encoder position during rotation. The index pulse has a duration of a
track position pulse. We recommend to always perform the latch process in
the same rotational direction.
2.1.1.7 Process
Image
Using the I/O module 750-634, a 5 byte input and output process image can be
transferred to the fieldbus coupler / controller via one logical channel. The
data sent and received is stored in 2 output bytes (D0, D1) and 5 input bytes
(D0, D1, D2, D3, D4). The output bytes D2 ... D4 are reserved and without
function. One control byte (C) and one status byte (S) are used to control the
data flow.
Attention
The representation of the process data of some I/O modules or their
variations in the process image depends on the fieldbus coupler/-controller
used. Please take this information as well as the particular design of the
respective control/status bytes from the section "Fieldbus Specific Design of
the Process Data" included in the description concerning the process image
of the corresponding coupler/controller.
Input Data
Output Data
S
Status byte
C
Control byte
D0
Counter value byte 0 (LSB)
D0
Counter set value byte 0 (LSB)
D1
Counter value byte 1 (MSB)
D1
Counter set value byte 1
(MSB)
D2
Signal A, B and C /
Cycle duration byte 2 (MSB)
D2 reserved
D3
Latch value byte 0 (LSB) /
Cycle duration byte 0 (LSB)
D3 reserved
D4
Latch value byte 1 (MSB) /
Cycle duration byte 1
D4 reserved