Danfoss MCO 305 Design Manual page 201

MCO 305 Design Guide
33-27 Offset Filter Time
SYNCOFFTIME
Range [Unit]
0 – MLONG [ms]
Function
Compensation velocity of an offset (1. synchronize;
2. new offset)
The Offset Filter Time also influences the way, how
a new Position Offset for Synchronization (par. 33-
12) value is handled. The offset which has to be
realized will be done step by step. The step which
is realized every sample time (ms) is calculated as
follows:
par. 33 - 17 Master
step size
par. 33 - 27 Offset
So it will take Offset Filter Time to realize an offset
of par. 33-17 Master Marker Distance . The Offset
Filter Time also has influence on the marker start
correction and on the correction of marker error
(see par. 33-29 Filter Time for Marker Correction ).
33-28 Marker Filter Configuration
SYNCMFPAR
Option
Normal SYNCMFTIME filter function
Constant value for the Marker Filter
No correction of SYNCFACT
Time constant based on Filter Time
for Marker Correction SYNCMFTIME
Only smoothing of the correction
value, time constant as [4]
Execute always marker distance
averaging.
Function
SYNCMFPAR is used to influence the behavior of
marker filtering, see SYNCMFTIME.
The following values are bit valences and can be
combined with each other:
0 = Normal filter function, see par. 33-29 Filter
Time for Marker Correction SYNCMFTIME
1 = Instead of the dynamic marker filter constant
a constant value of
SYNCMFTIME / 300 is used.
2 = Gear correction is not executed.
default setting
__ Parameter Reference __
0
Marker Distance
Filter Tim e (integer part)
[0]
[1]
[2]
[4]
[16]
[64]
[ ] value for use in communication via serial communication port
®
MG.33.L4.02 – VLT is a registered Danfoss trademark
4 = The Filter Time for Marker Correction (par.
33-29) is used instead of the Offset Filter
Time (par. 33-27) to calculate the time
constant for the correction value filter
(G_Korrektur)
16 = Instead of calculation of the filtered marker
distance and deviation, only the correction
value is smoothed by a PT filter. Time
constant for that filter on bit valence 4 basis
(see above).
64 = Marker averaging and marker check are also
executed when SYNCM is inactive.
33-29 Filter Time for Marker Correction
SYNCMFTIME
Range [Unit]
0 – MLONG [ms]
0 = Off;
if par. 33-26 Velocity Filte r is
negative, the marker correction is
spread by SYNCVFTIME /100
Application Example
Newspaper manufacturing needed this sort of filte-
ring to synchronizing a chain to the newspaper
stream coming from a printing machine. Because
the newspaper stream is not quite constant, the
problem is that if synchronized without filter the
movements of the chain are very hard and dyna-
mic. With all other sort of filters the system starts
swinging in sinusoidal waves.
When using this complex filter the synchronizing
work very well and solve the problem.
Function
SYNCMFTIME is given in ms and is used as follows:
NB!:
Master velocity filtering par. 33-26
Velocity Filte r is given in 1/1000 ms for a
better resolution, but the marker filtering
(SYNCMFTIME) is given in units of 1 ms.
Example:
SET SYNCVFTIME –50000
SET SYNCMFTIME 2000
This means, that the master velocity is filtered over
a period of 50 ms. A marker error is corrected
within a period of 2000 ms.
The actual filtered marker distance can be read out
with SYSVAR 4238 indices if this filter is activated
by setting SYNCMFTIME.
0
201