Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
Setting Up Turbo PMAC-Based Commutation and/or Current Loop
101
•
Ixx82 should contain the address of ADC B register for the feedback channel used (just as for
brushless motors) when the ADC A register is used for the rotor (armature) current feedback. The B
register itself should always contain a zero or near-zero value.
brushless motors) when the ADC A register is used for the rotor (armature) current feedback. The B
register itself should always contain a zero or near-zero value.
•
Ixx81 > 0: Any non-zero setting here makes Turbo PMAC do a “phasing read” instead of a search
move for the motor. This is a dummy read, because whatever is read is forced to zero degrees by the
settings of Ixx70 and Ixx71, but Turbo PMAC demands that some sort of phase reference be done.
(Ixx81=1 is fine.)
move for the motor. This is a dummy read, because whatever is read is forced to zero degrees by the
settings of Ixx70 and Ixx71, but Turbo PMAC demands that some sort of phase reference be done.
(Ixx81=1 is fine.)
•
Ixx84 is set just as for brushless motors, specifying which bits the current ADC feedback uses.
Usually, this is $FFF000 to specify the high 12 bits.
Usually, this is $FFF000 to specify the high 12 bits.
Special settings for brush motor direct PWM control:
•
Ixx70 = 0: This causes all values for the commutation cycle to be multiplied by 0 to defeat the
rotation of the commutation vector.
rotation of the commutation vector.
•
Ixx72 = 512 (90
o
e) if voltage and current numerical polarities are opposite, or1536 (270
o
e) if they are
the same. If the amplifier would use 683 (120
o
e) for a 3-phase motor, use 512 here; if it would use
1365 (240
o
e) for a 3-phase motor, use 1536 here.
•
Ixx96 = 1: This causes Turbo PMAC to clear the integrator periodically for the (non-existent) direct
current loop, which could slowly charge up due to noise or numerical errors and eventually interfere
with the real quadrature current loop.
current loop, which could slowly charge up due to noise or numerical errors and eventually interfere
with the real quadrature current loop.
Settings that do not matter:
•
Ixx71 (commutation cycle size) does not matter because Ixx70 setting of 0 defeats the commutation
cycle
cycle
•
Ixx75 (Offset in the power-on phase reference) does not matter because commutation cycle has been
defeated. Leaving this at the default of 0 is fine.
defeated. Leaving this at the default of 0 is fine.
•
Ixx83 (ongoing commutation position feedback address) doesn’t matter, since the commutation has
been defeated. Leaving this at the default value is fine.
been defeated. Leaving this at the default value is fine.
•
Ixx91 (power-on phase position format) does not matter, because whatever is read for the power-on
phase position is reduced to zero.
phase position is reduced to zero.
Testing PWM and Current Feedback Operation
CAUTION:
On many motor and drive systems, potentially deadly voltage and current levels
are present. Do not attempt to work directly with these high voltage and current
levels unless you are fully trained on all necessary safety procedures. Low-level
signals on Turbo PMAC and interface boards can be accessed much more safely.
are present. Do not attempt to work directly with these high voltage and current
levels unless you are fully trained on all necessary safety procedures. Low-level
signals on Turbo PMAC and interface boards can be accessed much more safely.
Introduction
Most of the time in setting up a direct PWM interface, do not execute all of the steps listed in these
sections (or the Turbo Setup program will do them automatically), but the first time this type of interface
is set up, or if there are problems, these steps will be of great assistance.
sections (or the Turbo Setup program will do them automatically), but the first time this type of interface
is set up, or if there are problems, these steps will be of great assistance.
All of these tests should be done with the motor disconnected from any loads for safety reasons. All
settings made as a result of these tests are independent of load properties, so will still be valid when the
load is connected.
settings made as a result of these tests are independent of load properties, so will still be valid when the
load is connected.
Before testing any of Turbo PMAC’s software features for digital current loop and direct PWM interface,
it is important to know whether the hardware interface is working properly. We will use PMAC’s M-
variables to access the input and output registers directly. The examples shown here use the suggested M-
variable definitions for Motor 1; for other motors there are equivalent suggested definitions shown in the
Examples section of the manual.
it is important to know whether the hardware interface is working properly. We will use PMAC’s M-
variables to access the input and output registers directly. The examples shown here use the suggested M-
variable definitions for Motor 1; for other motors there are equivalent suggested definitions shown in the
Examples section of the manual.