42
CHAPTER 7 – Programmation
SMT-BD2/m
3 - POSITIONER PARAMETERS
3.1
-
CONFIGURATION
OF
THE
PROGRAMMABLES
I/O
S
Inputs polarity
: defines the polarity of the optocoupled inputs START, STOP, WAIT, TEACH, JOG+, JOG-, IN1
to IN8: a signal that is not checked off with an X corresponds to an active 24 V input.
Sequence control
: The inputs IN1 to IN7 can be used for selecting sequences (checked off with an X). There are
maximum 128 sequences that can be selected this way by the inputs IN1 to IN7 (in binary code). The other inputs
can be used for the start condition.
Output polarity
: defines the polarity of the optocoupled outputs SEQ, POS, SPEED, OK, OUT1 to OUT8: a
signal that is not checked off with an X, corresponds to an active 24 V output.
Output pulse
: the outputs OUT1 to OUT8 can be defined as pulse outputs (checked off with an X) which duration
is defined by the parameter
output pulse duration
(1 to 16000 ms).
3.2
-
AXIS
POSITION
SCALING
Position resolution
: defines the number of position increments for one motor revolution (or one motor pole pitch
for a linear motor). The value range is between 400 and 4000000 pts.
The maximum possible value of the
Position resolution
parameter for a given application depends on the
Maximum speed
parameter value. The following condition must be answered for taking into account the
positioner speed limitation: Position resolution < 19 x 10
8
/ Maximum speed (rpm). If this condition is not
answered, the positioner speed scaling gain will be reduced according to the previous speed limitation (all the
sequences speed values will be reduced).
Decimal
: number of decimals for the position resolution (1, 2 or 3).
Unit
: defines the unit used for the position resolution (maximum 4 characters).
Example: For a resolution of 4 mm / motor revolution, if the number of decimals = 3, the parameters are:
Resolution = 4000, Decimal = 3, Unit = mm.
Following error threshold
: defines the triggering threshold of the position following error. When the servo loop
position error value is higher than the
following error threshold
parameter value, the position following error is
released. This parameter value must be adjusted correctly in order to get a good protection. Execute first the
desired operating cycles and reduce progressively the
following error threshold
value until the fault is triggered.
Then set the following error threshold at this value plus a margin of 30 to 50 %.
Maximum braking distance
: defines the limit value for the motor braking distance when the position following
error is released. This parameter value must be set according to the maximum motor speed and the available
amplifier current. When the position following error is released, the amplifier speed reference value is set at zero
and the motor is braking in the shortest time according to the available amplifier current. The amplifier is then
disabled as soon as the zero speed is reached. However, if the motor braking distance exceeds the
maximum
braking distance
parameter value during the braking phase, the amplifier is immediately disabled. This braking
distance monitoring function allows to protect the operator and the machine against uncontrolled motor
movements that could be generated by a drive failure. If the
maximum braking distance
parameter value is set
at zero, when the position following error is released, the amplifier is immediately disabled without the braking
phase and the motor freewelling.
The
maximum braking distance
parameter is also taken into account when an hardware limit switch (FC+ or FC-
) is activated. In this case, the amplifier speed reference value is set at zero and the motor is braking in the
shortest time according to the available amplifier current. During the braking phase, the following error detection is
not active. However, if the motor braking distance exceeds the
maximum braking distance
parameter value
during the braking phase, the amplifier is immediately disabled and a position following error is released. If the
maximum braking distance
parameter value is set at zero, when an hardware limit switch is activated, the
following error detection is still active. So, if a position following error is released during the braking phase, the
amplifier is disabled and the motor freewelling.
Deadband
: defines the deadband for the position controller. The deadband is desactivated when the parameter is
set at 0.
CLR input enable
: when activated (checked off), allows to use the INDEX input for re-initializing the position
counter: at the inactive-active transition of this signal, the
Clear position
parameter value will be loaded in the
position counter.
