EVAL6235 board configuration

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EVAL6235 board configuration

The schematic of the EVAL6235 board is shown in Figure 9. To use the EVAL6235 board

with practiSPIN system, the following configuration settings must be made on the

EVAL6235:

1.

Component updates: depending on the revision of the board, some or all of the

following changes may be required (or desirable):

a)

To assure safe overcurrent operation:

–

Change C6 and C7 to 5.6 nF

–

Change R6 to 100 k

Ω and remove R2

b)

To assure an adequate 5 V supply, R1 may need to be changed. The minimum

value for R1 is (Vs-5)/(0.03+I)

Ω . Where: Vs is the supply voltage and I is any

additional load (such as Hall sensors) placed on the5 V supply (in amps).

2.

JP1 and JP2: install JP1 and JP2 to enable the on-board 5 Vdc supply.

3.

Switches: place all four switches in the down (away from U2) position.

4.

R22: adjust multi-turn trim pot R22 fully clockwise.

Note:

A slight click can be heard from the pot when it reaches its end of travel.

5.

R10: adjust multi-turn pot R10 to the middle of its range. This pot sets the off time of the

cycle by cycle current controller and can be fine tuned while observing the motor

current on an oscilloscope or by simply adjusting to raise the frequency of the audible

switching noise to an inaudible level if required.

6.

Hall sensors: connect the hall sensors of the BLDC motor at CN5. Connect the power

supply wires from the hall sensors at pins GND and P5V. Hall sensors are notorious for

being destroyed by reversed polarity! Know, don't guess, the proper polarity! Connect

H1, H2, and H3 signals to their respective pins.

7.

Motor connections: connect the three motor armature wires at CN3 being careful to

match the phasing to the hall sensor connections. Please refer to the L6235 data sheet

for a description of the proper phase relationship between the motor phases and the

Hall sensors.

Note:

There are six possible ways to connect the three armature wires to CN3. While only one

connection will give proper performance, one or two of the other possible connection may

cause the motor to turn but with very poor performance and, perhaps, high motor currents

even if the system is unloaded.

8.

Power supply: connect, but do not energize, a 12 to 48 Vdc power supply at CN1

9.

Using a 34 pin ribbon cable connect the EVAL6208PD board to the control interface

board. The two boards should be placed on the bench so that their 34 pin headers are

side by side with the ribbon cable going straight across. Set the following on the ST7

interface board.

10. WJ1: install WJ1 on the ST7 based control interface board. This allows 5 Vdc power to

be obtained from the target board.

11. JP1 and JP2 and R18: install the JP1 and JP2 jumpers to short the center and left pins

together. This is critical as excessive motor current can result from misplacement of

these jumpers! Set potentiometer R18 to about 50%.