User's Manual
PMAC2 User Manual
Setting Up PMAC2 Commutation (Direct PWM or Sine Wave) 45
It is advisable to create a table listing the values of M124 through M128 for each position. The following
table is a typical position table for these values.
Step M179 M129 Cycle
Position
Physical
Position
M101
(Counts)
M126
(U)
M125
(V)
M124
(W)
M128
(Tuvw)
1 +3000 -1500
-30
o
3:30 -9001 0 1 0 2
2 +1500 -3000
-90
o
2:30 -9343 1 1 0 6
3 -1500 -1500
-150
o
1:30 -9673 1 0 0 4
4 -3000 +1500
+150
o
12:30 -10030 1 0 1 5
5 -1500 +3000 +90
11:30 -10375 0 0 1 1
6 +1500 +1500
+30
o
10:30 -10709 0 1 1 3
1 +3000 -1500
-30
o
9:30 -11050 0 1 0 2
Using the Test Results
To execute a power-on phasing using the hall-effect sensors, use new modes of the Ix81 power-on phase
position parameter or write a simple PLC program that executes once on power-up/reset.
Setting bit 23 of Ix81 to 1 specifies a hall-effect power-on phase reference. In this case, the address
portion of Ix81 specifies a PMAC X-address, usually that of the flag register used for the motor, the same
address as in Ix25.
PMAC expects to find the hall-effect inputs at bits 20, 21, and 22 of the specified register. In a flag
register, these bits match the CHWn, CHVn, and CHUn inputs, respectively. Hall-effect inputs are
traditionally labeled U, V, and W.
The hall-effect signals must each have a duty cycle of 50% (180
o
e). PMAC can use hall-effect
commutation sensors separated by 120
o
e. There is no industry standard with hall-effect sensors as to
direction sense or zero reference, so this must be handled with software settings of Ix81.
Bit 22 controls the direction sense of the hall-effect sensors as shown in the following diagrams, where a
value of 0 for bit 22 is standard and a value of 1 is reversed:
U
V
W
-30 30 90 150 -150 -90
1
0
1
0
1
0
30 -30 -90 -150 90150
Standard:
Reversed:
UVW Value:132645
Figure 13 Hall-Effect Waveforms With Zero Offset
This diagram shows the hall-effect waveforms with zero offset, defined such that the V-signal transition
when the U-signal is low (defined as the zero point in the hall-effect cycle) represents the zero point in
PMAC’s commutation cycle.
If the hall-effect sensors do not have this orientation, bits 16 to 21 of Ix81 can be used to specify the
offset between PMAC’s zero point and the hall-effect zero point. These bits can take a value of 0 to 63
with units of 1/64 of a commutation cycle (5.625
o
e).
The offset can be computed using the mapping test shown above. In our example, the the hall effect zero
(HEZ) point was found to be between +30
o
e and +90
o
e, so we will call +60
o
e. The offset value can be
computed as: