Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 35)

Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011 35
Detailed Drive Operation Chapter 1
Current Limit The following methods are available for a drive to use to protect itself from an
overcurrent or overload condition.
• Instantaneous Over Current Trip - This is a feature that instantaneously
trips or faults the drive if the output current exceeds this value. The value is
fixed by hardware and is typically 250% of drive rated amps. This feature
cannot be disabled.
• Software Over Current Trip - This is a configurable trip function. If
parameter 377 [Inv OL Trip Cnfg] is set to 2 “FltCoastStop” (Fault Coast
to Stop), the drive will trip on an inverter overload. This will occur when
the Open Loop or Closed Loop IT function has detected an overload
condition. See the
Drive Overload on page 45 section for a description of
the Open Loop and Closed Loop IT functions.
• Software Current Limit - This feature selectively limits the current the
drive will provide based on the several factors. The value of parameter 356
[Mtr Current Lim] will limit the current to the user changeable level; the
range is 105% of motor flux current to 800% of the motor nameplate rated
full load amps, entered in parameter 2 [Motor NP FLA]. The Open Loop
IT function can also limit the output current if the calculation determines
it is in the overload area of operation. The Open Loop IT function and the
motor current limit parameters are routed to a minimum selection, the
algebraic minimum of the inputs is used as the current limit. Also, the
Closed Loop IT function can limit the current output from the drive. The
Closed Loop IT function and the torque current reference are compared
and the algebraic minimum is used for the torque current reference. See the
Drive Overload on page 45 section for a description of the Open Loop and
Closed Loop IT functions.
Datalinks Datalinks are used to transfer I/O data from a communication adapter [for
example, ControlNet (20-COMM-C) or DeviceNet (20-COMM-D), or
EtherNet/IP (20-COMM-E)] to a controller. Datalinks allow parameter values
to be changed without using messaging.
Configuring Datalinks
This section contains information on configuring the Datalink parameters in the
PowerFlex 700S. There are also parameters in the communication adapters that
must be configured to use Datalinks. Refer to the section on “Using Datalinks” in
the individual adapter user manuals for more information.
• 20-COMM-C ControlNet Adapter User Manual,
20COMM-UM003
• 20-COMM-D DeviceNet Adapter User Manual,
20COMM-UM002
• 20-COMM-E EtherNet/IP Adapter User Manual,
20COMM-UM010