Arcus PMX-4EX-SA, Руководство пользователя

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PMX-4EX-SA Manual page 52 Rev 3.11
6.22. StepNLoop Closed Loop Control
PMX-4EX-SA features a closed-loop position verification algorithm called
StepNLoop (SNL). The algorithm requires the use of an incremental encoder.
SNL performs the following operations:
1) Position Verification: At the end of any targeted move, SNL will
perform a correction if the current error is greater than the tolerance
value.
2) Delta Monitoring: The delta value is the difference between the actual
and the target position. When delta exceeds the error range value, the
motor is stopped and the SNL Status goes into an error state. Delta
monitoring is performed during moves – including homing and jogging.
To read the delta value, use the
DX[axis] command.
See Table 6.13 for a list of the SNL control parameters.
SNL Parameter Description Command
StepNLoop Ratio
Ratio between motor pulses and encoder counts.
This ratio will depend on the motor type, micro-
stepping, encoder resolution and decoding multiplier.
Value must be in the range [0.001 , 999.999].
SLR[axis]
Tolerance
Maximum error between target and actual position
that is considered “In Position”. In this case, no
correction is performed. Units are in encoder counts.
SLT[axis]
Error Range
Maximum error between target and actual position
that is not considered a serious error. If the error
exceeds this value, the motor will stop immediately
and go into an error state.
SLE[axis]
Correction Attempt
Maximum number of correction tries that the
controller will attempt before stopping and going into
an error state.
SLA[axis]
Table 6.13
A convenient way to find the StepNLoop ratio is to set EX=0, PX=0 and move the
motor +1000 pulses. The ratio can be calculated by dividing 1000 by the
resulting EX value. Note that the value must be positive. If it is not, then the
direction polarity must be adjusted. This test should be performed while
StepNLoop is disabled.
To enable/disable the SNL feature use the
SL[axis] command. To read the SNL
status, use SLS[axis] command. See Table 6.14 for a list of the SLS[axis] return
values.