User's Manual

PMAC2 User Manual
36 Setting Up PMAC2 for Sine-Wave Output Control
Command Output Address: Ix02
Ix02 instructs PMAC2 where to place its output commands for Motor x by specifying the address. The
default values of Ix02 use the DAC registers A and B for Machine Interface Channel n, where n=x, by
specifying the address of DAC register A. Ix02 seldom needs to be changed from the default value for
DAC applications. Usually the values used are shown in the DAC Command Output Addresses table.
Chan # 1 2 3 4 5 6 7 8
Hex
$C002 $C00A $C012 $C01A $C022 $C02A $C032 $C03A
When performing sine-wave output control over the MACRO ring, Ix02 points to the first of a set of two
MACRO output registers for the node used. Typically, the values used which are shown in the MACRO
Command Output Registers table, are dependent on whether MACRO Type 0 or Type 1 protocol is used:
Node # 0 1 4 5 8 9 12 13
Type 0
$C0A2 $C0A6 $C0AA $C0AE $C0B2 $C0B6 $C0BA $C0BE
Type 1
$C0A0 $C0A4 $C0A8 $C0AC $C0B0 $C0B4 $C0B8 $C0BC
Commutation Cycle Size: Ix70, Ix71
Ix70 and Ix71 define the size of the commutation cycle (electrical cycle). The cycle is equal to Ix71
divided by Ix70, expressed in encoder counts (after decode). Ix70 and Ix71 must both be integers, but the
ratio Ix71/Ix70 does not have to be an integer. Typically, on a rotary motor, Ix71 is set to the number of
counts per mechanical revolution, and Ix70 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.
Commutation Phase Angle: Ix72
Ix72 sets the angle from phase A to phase B as a fraction of the commutation cycle. PMAC2 splits the
commutation cycle (360
o
e) into 256 parts. For a 3-phase motor, the angle from A to B is either 1/3 of a
cycle (Ix72=85) or 2/3 of a cycle (Ix72=171). For a 2-phase or 4-phase motor, the angle from A to B is
either 1/4 of a cycle (Ix72=64) or 3/4 of a cycle (Ix72=192).
The proper choice of Ix72 is dependent on the commutation feedback encoder’s direction sense as
determined by its wiring and the encoder decode variable I9n0, and on the wiring of the phases of the
motor. This choice is generally determined experimentally through a test explained below. Changing
Ix72 between, say, 85 and 171 is equivalent to exchanging two phase wires of the motor.
Commutation Feedback Address: Ix83
Ix83 specifies the address of the register used for the commutation position feedback. This is almost
always the address of the encoder phase position register for Channel n in PMAC2’s gate array IC, where
n = x. This address is the default value for Ix83. Usually the values used are:
Chan # 1 2 3 4 5 6 7 8
Hex
$C001 $C009 $C011 $C019 $C021 $C029 $C031 $C039
When performing sine wave control over the MACRO ring, Ix83 points to the position feedback register
for the node used. These are Y-registers, so bit 19 of Ix83 must be set to 1. Typically, the values used are
dependent on whether MACRO Type 0 or Type 1 protocol is employed for the node:
Node # 0 1 4 5 8 9 12 13
Type 0
$8C0A3 $8C0A7 $8C0AB $8C0AF $8C0B3 $8C0B7 $8C0BB $8C0BF
Type 1
$8C0A0 $8C0A4 $8C0A8 $8C0AC $8C0B0 $8C0B4 $8C0B8 $8C0BC