Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
Setting Up Turbo PMAC-Based Commutation and/or Current Loop
89
SETTING UP TURBO PMAC-BASED COMMUTATION AND/OR
CURRENT LOOP
CURRENT LOOP
This section provides detailed instructions for the step-by-step manual setup of motor phase commutation
and/or digital current-loop closure within the Turbo PMAC. Few users will do these steps manually;
most will use the automated procedures of the Turbo Setup program on the PC, even for the setup of the
first unit. The instructions in this section are for the user who wants a full understanding of the Turbo
PMAC algorithms and how they are set up for a particular application.
and/or digital current-loop closure within the Turbo PMAC. Few users will do these steps manually;
most will use the automated procedures of the Turbo Setup program on the PC, even for the setup of the
first unit. The instructions in this section are for the user who wants a full understanding of the Turbo
PMAC algorithms and how they are set up for a particular application.
Beginning Setup of Commutation
If Turbo PMAC is to perform the commutation of a motor, it must do more than simply close the
position/velocity-loop servo for the motor. Several parameters must be set up correctly to configure the
commutation.
position/velocity-loop servo for the motor. Several parameters must be set up correctly to configure the
commutation.
The first steps in setting up the commutation are common whether Turbo PMAC is performing the current
loop closure (direct PWM output mode) or not (sine-wave output mode). These steps are described in this
section. The next steps differ based on which mode is used; these are described in the next two sections,
only one of which is used for a particular motor. Finally, the last steps in the setup of commutation are
again common to the two modes of operation; these are described in the following section.
loop closure (direct PWM output mode) or not (sine-wave output mode). These steps are described in this
section. The next steps differ based on which mode is used; these are described in the next two sections,
only one of which is used for a particular motor. Finally, the last steps in the setup of commutation are
again common to the two modes of operation; these are described in the following section.
Commutation Enable: Ixx01
If Turbo PMAC is performing the commutation for Motor xx using a directly addressed (not over
MACRO) Servo IC encoder register, Ixx01 must be set to 1 to enable the commutation and use an X-
register for commutation feedback (as addressed by Ixx83). If Turbo PMAC is performing the
commutation for Motor xx using a Servo IC on a MACRO Station, Ixx03 must be set to 3 to enable the
commutation and use a Y-register for commutation feedback. (If Turbo PMAC is performing the digital
current loop closure, it must also perform the phase commutation for the motor.)
MACRO) Servo IC encoder register, Ixx01 must be set to 1 to enable the commutation and use an X-
register for commutation feedback (as addressed by Ixx83). If Turbo PMAC is performing the
commutation for Motor xx using a Servo IC on a MACRO Station, Ixx03 must be set to 3 to enable the
commutation and use a Y-register for commutation feedback. (If Turbo PMAC is performing the digital
current loop closure, it must also perform the phase commutation for the motor.)
Note:
Direct PWM control of brush motors with digital current loop utilizes Turbo
PMAC’s commutation algorithms even though the motor does not require
electronic commutation; Ixx01 must be set to 1 or 3 for this case.
PMAC’s commutation algorithms even though the motor does not require
electronic commutation; Ixx01 must be set to 1 or 3 for this case.
Commutation Cycle Size: Ixx70 & Ixx71
Ixx70 and Ixx71 define the size of the commutation cycle (electrical cycle). The cycle is equal to Ixx71
divided by Ixx70, expressed in encoder counts (after decode). Ixx70 and Ixx71 must both be integers, but
the ratio Ixx71/Ixx70 does not have to be an integer. On a rotary motor, typically Ixx71 is set to the
number of counts per mechanical revolution, and Ixx70 is set to the number of pole-pairs (half of the
number of poles) for the motor, which is equal to the number of commutation cycles per mechanical
revolution.
divided by Ixx70, expressed in encoder counts (after decode). Ixx70 and Ixx71 must both be integers, but
the ratio Ixx71/Ixx70 does not have to be an integer. On a rotary motor, typically Ixx71 is set to the
number of counts per mechanical revolution, and Ixx70 is set to the number of pole-pairs (half of the
number of poles) for the motor, which is equal to the number of commutation cycles per mechanical
revolution.
When commutating across the MACRO ring with the Type 1 protocol used by Delta Tau MACRO
products, the standard position feedback reported in Register 0 is in units of 1/32 count. If this is used as
the commutation position feedback, as specified by Ixx83, the units of Ixx71/Ixx70 must also be in 1/32
of a count. For example, if a 4-pole (2-electrical-cycle) motor has a 2000-line (8000-count) encoder,
instead of setting Ixx70 to 2 and Ixx71 to 8000, Ixx70 should be set to 2 and Ixx71 should be set to
256,000.
products, the standard position feedback reported in Register 0 is in units of 1/32 count. If this is used as
the commutation position feedback, as specified by Ixx83, the units of Ixx71/Ixx70 must also be in 1/32
of a count. For example, if a 4-pole (2-electrical-cycle) motor has a 2000-line (8000-count) encoder,
instead of setting Ixx70 to 2 and Ixx71 to 8000, Ixx70 should be set to 2 and Ixx71 should be set to
256,000.
When performing direct PWM control of brush motors, the commutation algorithm must be fooled to
create DC output instead of its usual AC output. This is best done by setting Ixx70 and Ixx71 to 0.
create DC output instead of its usual AC output. This is best done by setting Ixx70 and Ixx71 to 0.