Galil DMC-1700, DMC-1800 user manual b. Connect Sinusoidal Commutation Motors

Step 8b. Connect Sinusoidal Commutation Motors

When using sinusoidal commutation, the parameters for the commutation must be determined and saved in the controllers non-volatile memory. The servo can then be tuned as described in Step 9.

Step A. Disable the motor amplifier

Use the command, MO, to disable the motor amplifiers. For example, MOX will turn the X axis motor off.

Step B. Connect the motor amplifier to the controller.

The sinusoidal commutation amplifier requires 2 signals, usually denoted as Phase A & Phase

B.These inputs should be connected to the two sinusoidal signals generated by the controller. The first signal is the axis specified with the command, BA (Step 6). The second signal is associated with the highest analog command signal available on the controller - note that this axis was made unavailable for standard servo operation by the command BA.

When more than one axis is configured for sinusoidal commutation, the controller will assign the second phase to the command output which has been made available through the axes reconfiguration. The 2nd phase of the highest sinusoidal commutation axis will be the highest command output and the 2nd phase of the lowest sinusoidal commutation axis will be the lowest command output.

It is not necessary to be concerned with cross-wiring the 1st and 2nd signals. If this wiring is incorrect, the setup procedure will alert the user (Step D).

Example: Sinusoidal Commutation Configuration using a DMC-1770

BAXZ

This command causes the controller to be reconfigured as a DMC-1750 controller. The X and Z axes are configured for sinusoidal commutation. The first phase of the X axis will be the motor command X signal. The second phase of the X axis will be the motor command F signal. The first phase of the Z axis will be the motor command Z signal. The second phase of the Z axis will be the motor command G signal.

Step C. Specify the Size of the Magnetic Cycle.

Use the command, BM, to specify the size of the brushless motors magnetic cycle in encoder counts. For example, if the X axis is a linear motor where the magnetic cycle length is 62 mm, and the encoder resolution is 1 micron, the cycle equals 62,000 counts. This can be commanded with the command:

BM 62000

On the other hand, if the Z axis is a rotary motor with 4000 counts per revolution and 3 magnetic cycles per revolution (three pole pairs) the command is

BM,, 1333.333

Step D. Test the Polarity of the DACs and Hall Sensor Configuration.

Use the brushless motor setup command, BS, to test the polarity of the output DACs. This command applies a certain voltage, V, to each phase for some time T, and checks to see if the motion is in the correct direction.

The user must specify the value for V and T. For example, the command BSX = 2,700

DMC-1700/1800 Chapter 2 Getting Started • 31