Danfoss VLT5000 SyncPos Operating Instructions Manual page 186

27 ENCODERTYPE
This parameter determines the type of encoder:
incremental or absolute.
Errors can occur when a linear absolute encoder is
used. A possible leap in the position data can be
detected with the encoder types "3" and "4" if it is
larger than the encoder resolution/2. The correction
is made by means of an artificial position value
which is calculated from the last velocity. If the error
continues for more than 100 read-outs (> 100 ms),
there will be no further correction which will then
indeed lead to a tolerated position error exceeded.
The total number of errors will be saved in an inter-
nal variable which can be read out via SYSVAR[16].
Content
Type of encoder for slave encoder (encoder 0)
Parameter Group
Axis parameter Encoder AXE
CAM-Editor: index card Encoder
Value range
0 ... 4, 100 ... 104
0 = Incremental encoder
1 = Absolute encoder, standard ca. 262 kHz
2 = Absolute encoder, ca. 105 kHz
3 = absolute encoder without overflow (linear) but
with error correction, approx. 262 kHz
4 = absolute encoder without overflow (linear) but
with error correction, approx. 105 kHz
100 ... 104 = like 0 ... 4, however, hardware monito-
ring of the encoder will be activated. Error 92
will be issued in case of open or short circuit.
NB!
The following commands cannot be used
with absolute encoders: DEF ORIGIN, HOME,
INDEX and WAITNDX.
NB!
The following commands can only be used
with absolute encoders if external markers
are used: IPOS, MIPOS.
MG.10.J8.02 – VLT is a registered Danfoss trade mark
Programmable SyncPos motion controller
28 POSDRCT
A normal requirement for the axis controller is that a
positive reference value brings about a positive
change of the position. If this is not the case (e.g.
encoder transposed or motor connected improperly),
the reference value can be reversed internally by
the parameter POSDRCT = 2.
In some applications it is desirable to reverse the
direction of rotation in user units. This is achieved by
the negative sign in POSDRCT.
Die Richtung der Synchronisation (Verhältnis zum
Master) kann durch negativen SYNCFACTM umge-
dreht werden.
The direction of rotation (relation to master) can be
turned by negative SYNCFACTM.
In the case of a synchronization in CAM-Mode, you
can determine a positive direction of rotation for the
slave with POSDRCT. This is a prerequisite for the
CAM functionality.
Content
Positive direction of rotation
★ 0
Parameter Group
Axis parameter Encoder AXE
CAM-Editor: index card Encoder
Value range
–2 ... 2
1 = No change, i.e. positive reference values
produce positive encoder values.
–1 = The sign of the user unit is reversed. Thus,
positive reference values produce positive
encoder values which are indicated as nega-
tive values, however. This applies to all outputs
(APOS, CPOS, ...), all user inputs (POSA,
POSR, ...) and all synchronization factors, as
well as the velocities (CVEL, HOME_VEL).
2 = The sign of the reference value is reversed
internally (plus becomes minus and vice
versa). This is equal to a reversal of the motor
leads, or a transposition of the A and B tracks
on the encoder.
–2 = Same as "2", i.e. the sign of the reference
value is reversed internally; in addition, the
sign of the user unit is negated as in "–1".
★ 1
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