Rockwell Automation SA500 Diagnostics, Troubleshooting Guide - Manual (Page 20)

3-4 SA500 Diagnostics, Troubleshooting, and Start-Up Guidelines
3.3 Alignment Test Mode
For SA500 drives controlling brushless DC motors, the resolver shaft and the rotor
shaft must be aligned in order to ensure that maximum torque is generated. Therefore,
an alignment procedure must be performed before the torque, speed, and position
minor loops are executed. The alignment procedure automatically determines the
offset required to bring the rotor and the stator fields 90° apart. This procedure must
be performed whenever the resolver has been disconnected from the motor for any
reason, including reversing cosine leads to the resolver.
Important: This procedure will cause the motor to move less than one revolution in
both forward and reverse direction for under three minutes. Uncouple the
motor from the load to run this test if this motion would be harmful to your
machine.
The programmer sets the Enable Resolver Alignment Test bit (register 100/1100, bit 1,
ALN_TST@) to request the PMI to execute the alignment procedure. Before the
alignment test can be executed, all of the following conditions are required:
• The interlock tests (described in section 2.3) must be passed successfully.
• The M-contactor, if configured, must be closed (described in section 2.4.1.2).
If any of the requirements are not met of if a fault is latched in the Drive Fault register
(202/1202), the PMI will remain in the idle mode.
If these requirements are met, the PMI will execute the alignment procedure.
When the alignment procedure is successfully completed, the PMI will set the
Alignment OK bit (register 200/1200, bit 1, ALN_OK@). The programmer can then
turn off the Enable Resolver Alignment Test bit. This will also turn off the Alignment
OK bit. The result of this test is written to the tunable variable RES_ALN% by the PMI.
If a problem is detected during the alignment procedure (e.g., the incorrect number of
motor poles or resolver type was entered during configuration), the Tuning Aborted
Warning bit (register 203/1203, bit 5, WRN_TUN@) is set. When the alignment
procedure is turned off, the PMI returns to the idle state.
!
ATTENTION: For brushless motor applications, changing any resolver
wiring, breaking the resolver coupling, replacing the resolver, or replacing
the motor and resolver for any reason requires that the shaft alignment
test be performed again. Resolver wiring changes always affect shaft
alignment. A resolver change and/or a new motor/resolver combination
will affect the shaft alignment. Improper shaft alignment can cause motor
overspeed when the motor is started. Failure to observe this precaution
could result in bodily injury.