Rockwell Automation 1395 Digital DC Drive FRN 5-10.10/9.30 - Manual (Page 100)

Chapter 5
Functional Description
5-14
In this example, the speed feedback is being provided by a DC tachometer.
The standard drive control is set up to use a digital Encoder for speed
feedback, therefore, the standard hardware of the drive does not have an
input for DC tach feedback. In this case, the DC tach feedback must be
provided through the Discrete Board as an analog input as shown in Figure
5.4. The speed feedback derived from the tach appears at Parameter 402,
and is linked to Parameter 156 which is the Tach Velocity input to the
Control Logic and is used for external speed feedback.
In a similar manner, information from the Control Logic is linked to Sink
parameters associated with Port A to provide digital and analog outputs
from the Discrete Board as shown in Figure 5.4. Data flow between the
Control Logic and other Adapter Boards may be traced in the same
manner. For detailed information pertaining to the hardware and
parameters associated with each Adapter Board, refer to the Installation
and Maintenance Manual for that specific board.
Auto-tuning The 1395 drive contains software that enables the drive to test and tune its
current loop, velocity loop and field flux loop upon command. These
features can be operated from the available program terminals or through a
PLC program. Several of these tests require that the motor be capable of
running at base speed. The choices available are detailed below.
– Current Loop Test. This feature checks the drive armature bridge for
shorts or open circuits, verifies that armature voltage sensing is operating
and measures the motor armature circuit.
– Current Loop Tune. This feature uses the information determined by
the current loop test to tune the drive current loop.
– Velocity Loop Motor Test This feature calculates the motor inertia by
running the motor under a controlled set of circumstances. The motor
must be disconnected from the load to run this test.
– Velocity Loop System Test. This feature calculates the system inertia by
running the motor under a controlled set of circumstances. The motor
must be connected to the load to run this test.
– Velocity Loop Tune. This feature programs the drive velocity loop gains
based on the information determined by the velocity loop motor and
system tests.
– Field Flux Tune. This feature calibrates the drive field flux table to the
actual motor field. The motor must be capable of running to complete
this procedure. Due to the reduction of available torque, it may be
necessary to disconnect the load to run this procedure.