Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
94
Setting Up Turbo PMAC-Based Commutation and/or Current Loop
Turbo PMAC has a PI (proportional-integral) digital current loop. There is only one set of gains, which
serves for both the direct current loop and the quadrature current loop. Tuning is best done on the direct
current loop, because this will generate no torque, and therefore no movement. The current-loop auto-
tuner in the PMAC Executive program uses the direct current loop to tune. This is valid even for
permanent-magnet brushless motors in which no direct current will be used in the actual application.
Current loop performance is not load-dependent, so the motor does not need to be attached to the load
during the tuning process. For position/velocity loop tuning, the load does need to be attached.
serves for both the direct current loop and the quadrature current loop. Tuning is best done on the direct
current loop, because this will generate no torque, and therefore no movement. The current-loop auto-
tuner in the PMAC Executive program uses the direct current loop to tune. This is valid even for
permanent-magnet brushless motors in which no direct current will be used in the actual application.
Current loop performance is not load-dependent, so the motor does not need to be attached to the load
during the tuning process. For position/velocity loop tuning, the load does need to be attached.
PMAC / PMAC2 Commutation with Digital Current Loop
Torque Command
from Position/
Velocity Servo
Magnetization
Current
Ix77
SG
Ix78
1/s
PMAC
Amplifier
PWM
PWM
PWM
V
a
V
b
V
c
E
ADC
ADC
i
a
i
b
dq
to
abc
Quadrature
Current
Command
DC
AC
V
a
V
b
V
c
abc
to
dq
I
a
I
b
+
+
Θ
r
Θ
e
Θ
Direct Current
Command
PI
Direct Current Loop
+
-
+
-
P
I
d
Quadrature Current Loop
PI
+
-
+
-
P
I
q
V
d
V
q
I
d
I
q
Hardware Setup
The connection between Turbo PMAC and the direct PWM digital amplifier is made through a Mini-D 36-
pin connector with a standard pin-out defined by Delta Tau. This connector contains the PWM command
signals, the ADC feedback signals, and the amplifier-enable and fault handshake signals. Usually, this
connector is found on an Acc-8F breakout board for board-level Turbo PMAC2s, on Acc-24E2 PWM axis-
interface boards for the UMAC and on the front panel of a QMAC with the PWM option ordered.
The connection between Turbo PMAC and the direct PWM digital amplifier is made through a Mini-D 36-
pin connector with a standard pin-out defined by Delta Tau. This connector contains the PWM command
signals, the ADC feedback signals, and the amplifier-enable and fault handshake signals. Usually, this
connector is found on an Acc-8F breakout board for board-level Turbo PMAC2s, on Acc-24E2 PWM axis-
interface boards for the UMAC and on the front panel of a QMAC with the PWM option ordered.
Position feedback, from an encoder or possibly a resolver, typically comes directly back to the Turbo
PMAC; there is no need for position feedback in the drive in this mode of operation.
PMAC; there is no need for position feedback in the drive in this mode of operation.
For a three-phase motor, whether delta-wound or (more commonly) Y-wound, each of the three phase
leads of the motor is connected to one of the phase outputs of the amplifier. Exchanging any two of the
three leads switches the direction sense of the outputs; proper matching of this to feedback will be
evaluated in a setup test. Rotating the three motor leads with respect to the amplifier outputs changes the
commutation cycle’s zero point with respect to any absolute sensor’s zero point.
leads of the motor is connected to one of the phase outputs of the amplifier. Exchanging any two of the
three leads switches the direction sense of the outputs; proper matching of this to feedback will be
evaluated in a setup test. Rotating the three motor leads with respect to the amplifier outputs changes the
commutation cycle’s zero point with respect to any absolute sensor’s zero point.
For a DC brush motor driven from a 3-phase power block amplifier, the two motor leads must be
connected between the first and third amplifier outputs, corresponding to the A and C outputs from the
Turbo PMAC.
connected between the first and third amplifier outputs, corresponding to the A and C outputs from the
Turbo PMAC.
Turbo PMAC Parameter Setup
Much of the Turbo PMAC interface hardware is software-configurable through I-variables. This section
provides basic information on each of the I-variables that is important in this type of application. There is
a detailed description of each I-variable in the Software Reference Manual.
provides basic information on each of the I-variables that is important in this type of application. There is
a detailed description of each I-variable in the Software Reference Manual.