S94P01C -e1
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6.3.1.3 Position Mode
In this mode the drive reference is a pulse-train applied to P3.1-4 terminals, if the
parameter “Reference” is set to “External”. Otherwise the reference is taken from
the drive’s internal variable. (Refer to the PositionServo Programming Manual for
details).
P3.1-4 inputs can be configured for two types of signals: step and direction and
Master encoder quadrature signal. Refer to section 5.2.1 for details on these
inputs connections. Refer to section 8.3 for details about positioning and gearing.
When the Reference is set to Internal, the drives reference position, (theoretical
or Target position), is generated by trajectory generator. Access to the trajectory
generator is provided by motion statements, MOVEx and MDV, from the User
Program. (Refer to the PositionServo Programming Manual for details).
6.3.2 Drive PWM frequency
This parameter sets the PWM carrier frequency. Frequency can be changed only
when the drive is disabled. Maximum overload current is 300% of the drive rated
current when the carrier is set to 8kHz. It is limited to 250% at 16kHz.
6.3.3 Current Limit
The CURRENT LIMIT setting determines the nominal currents, in amps RMS per
phase, which output to the motor phases. To prevent the motor from overloading,
this parameter is usually set equal to the motor nominal (or rated) phase current. If
MotionView (6.04) or higher is used, the Current Limit is set equal to the nominal motor
phase current by default when a motor model is selected. To modify this parameter,
refer to section 6.3.23.
6.3.4 8 kHz Peak Current Limit and 16 kHz Peak Current Limit
Peak Current Limit sets the motor RMS phase current that is allowed for up to 2
seconds. After this two second limit, the drive output current to motor will be reduced
to the value set by the Current Limit parameter. When the motor current drops below
nominal current for two seconds, the drive will automatically re-enable the peak
current level. This technique allows for high peak torque on demanding fast moves
and fast start/stop operations with high regulation bandwidth. If 8 kHz is used for Drive
PWM frequency, use the parameter 8 kHz Peak Current Limit, otherwise, use 16 kHz
Peak Current Limit.
If MotionView (6.04) or higher is used, the Peak Current Limit is set equal to 2.5
times the nominal motor phase current by default when a motor model is selected. To
prevent motor from overloading, the Peak Current Limit shall be set no higher than the
maximum motor current. Otherwise, the motor may be damaged due to overheating.
To modify this parameter, refer to section 6.3.23.
6.3.5 Analog Input Scale (current scale)
This parameter sets the analog input sensitivity for current reference used when the
drive operates in torque mode. Units for this parameter are A/Volt. To calculate this
value use the following formula:
Iscale = Imax / Vin max
Imax
maximum desired output current (motor phase current RMS)
Vin max max voltage fed to analog input at Imax
Example: Imax = 5A (phase RMS)
Vin max = 10V
Iscale = Imax / Vin max
= 5A / 10V = 0.5 A / Volt (value to enter)
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