Galil DMC-3425 user manual If Hall Sensors are Available

generated by the controller. The first signal is the main controller motor output, ACMD. The second signal utilizes the second DAC on the controller and is brought out on the ICM-1460 at pin 38 (ACMD2).

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).

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 you are using 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 <CR>

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

BM 1333.333 <CR>

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: BS 2,700 <CR>

will test the brushless axis with a voltage of 2 volts, applying it for 700 milliseconds for each phase. In response, this test indicates whether the DAC wiring is correct and will indicate an approximate value of BM. If the wiring is correct, the approximate value for BM will agree with the value used in the previous step.

Note: In order to properly conduct the brushless setup, the motor must be allowed to move a minimum of one magnetic cycle in both directions.

Note: When using Galil Windows software, the timeout must be set to a minimum of 10 seconds (time-out = 10000) when executing the BS command. This allows the software to retrieve all messages returned from the controller.

If Hall Sensors are Available:

Since the Hall sensors are connected randomly, it is very likely that they are wired in the incorrect order. The brushless setup command indicates the correct wiring of the Hall sensors. The hall sensor wires should be re-configured to reflect the results of this test.

The setup command also reports the position offset of the hall transition point and the zero phase of the motor commutation. The zero transition of the Hall sensors typically occurs at 0°, 30° or 90° of the phase commutation. It is necessary to inform the controller about the offset of the Hall sensor and this is done with the instruction, BB.

Step E. Save Brushless Motor Configuration

It is very important to save the brushless motor configuration in non-volatile memory. After the motor wiring and setup parameters have been properly configured, the burn command, BN, should be given.

24 • Chapter 2 Getting Started DMC-3425