Trinamic SIXpack 2, Руководство пользователя

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SIXpack 2 – Manual (V1.10 / January 29
th
, 2010) 30
6.4.4 Automatic reference search
The SIXpack 2 provides the possibility to start an automatic reference search at identified lost of steps. To activate
this function set the Flag MT_TESTNULL (command
SetMotorParameters , CMD $15). The intern position counter will
be compared with the status of the reference switch. If the reference switch reacts at wrong position or does not
react at internally logic position, a reference search is started and the flag STOPFLAG (command
GetPositionAndActivity , CMD $20) set.
6.4.5 Adjusting activity zone of reference switch
Mechanical inaccuracy may lead to reaction of the reference switch a few steps too early or too late. If an
automatic reference search (MT_TESTNULL) is used this may start unintended reference searches. It is possible to
define a zone around the zero-point in which the status of the reference switch is not checked using the
commands
SetNullPointOffset , (CMD $18) variable
TestNullRange
.
Figure 6.3: Coordinate transformation using „NullPointOffset“
6.4.6 Compensation of reference switch delay
At use of mechanic reference switches the problem of a delay time problem between mechanic and electronic
status change occurs often. To avoid dysfunction it is possible to delay the request of the reference switch signal
with
PowerDownDelay
. It is set and used in SetCurrentControl , CMD $11. MT_DELAYTESTNULL is set and
PowerDownDelay
is 500 in basic configuration.
NOTE:
PowerDownDelay
is used for “power down”- delay (command SetCurrentControl , CMD $11), also.
6.4.7 Elimination of glitches
In standard configuration the input signal at Refln is debounced for 22 ms. The change of levels has to be
constant in this time to be interpreted. This value is set with variable
DebouncingTime
(command
SetRefSearchParameters , CMD $16).
6.4.8 Adjusting reference search velocity
Fast reference search is activated in standard configuration (Flag MT_FASTREF of command SetMotorParameters ,
CMD $15). At this configuration the axis is moved at reference search with the velocity set in variable VRefMax
(default VrefMax =100).
CAUTION: If MT_FASTREF is used the length of the axis has to be defined in the variable
Poslimit
. Otherwise no
correct reference search is possible. If MT_FASTREF is not set
Poslimit
is not imperative. The reference search
will be with a fixed velocity of 1.