
SM-Universal Encoder Plus User Guide
51
Issue Number: 6
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6.4
Marker inputs
A marker channel input is only optional when operating with either of the following
incremental encoders:
Ab
Ab.SErvo
Fd
Fd.SErvo
Fr
Fr.SErvo
When the marker channel input becomes active this can be used to
1.
Reset the encoder position Pr
x.05
and Pr
x.06
and set the marker flag Pr
x.08
(Pr
x.07
should = 0)
2.
Set the marker flag Pr
x.08
(Pr
x.07
should = 1)
When the position is reset by the marker channel input, Pr
x.05
and Pr
x.06
are reset to
zero. The marker flag is set each time the marker input becomes active, but it is not
reset by the drive, and so this must be done by the user.
Marker reset data
Each time the marker becomes active the non-marker position values in Pr
x.29
revolution counter Pr
x.30
position and Pr
x.31
fine position are sampled and stored in
Pr
x.32
marker revolution counter, Pr
x.33
marker position and Pr
x.34
marker fine
position.
Non marker reset data
Pr
x.29
, Pr
x.30
, and Pr
x.31
positional information is taken from the position feedback
device with these not being affected by the marker inputs.
6.5
Marker outputs
A simulated marker output is available (Pr
x.38
) with either Fd, Fd.locK, Ab or Ab.locK,
H.drv or H.int as the simulated encoder output mode (Pr
x.28
) and a simulated encoder
output source has been defined (Pr
x.24
).
The marker pulse is simulated if the marker output port is not being used for the RS485
freeze input with the marker being synchronised with the zero count, and the duration is
calculated from the current position (taken every 250
µ
s) and the change in position.
The marker is output when both the A and B quadrature signals or F frequency is high
(when the source defined in Pr
x.24
reaches 0).
If the source is the drive position (Pr
3.29
) or any SM-Universal Encoder Plus (Pr
x.05
),
and the source's marker reset is enabled (Pr
3.31
= 0, or Pr
x.07
= 0), the source will
become synchronised to the marker reset position:
In AB or FD modes (normal marker synchronisation):
When a marker is detected by the input source (the drive or SM-Universal Encoder
Plus) the marker position based on the non-marker reset position is transferred within
500
µ
s.
The simulator reacts to this change in marker position in the next 250
µ
s period by
sending out the change in position resulting from the marker correction. This change
could be large when the first marker input is received by the source. The simulator is
limited to 500kHz, so many 250
µ
s periods at maximum output frequency could be used
if the position change is large. The marker is output as normal when the output position
passes through zero.
This system does not discard lines but could include a delay before the marker is output
while the position change caused by the first marker input is output at the maximum
output frequency.