SPINX1 4
OPERATION
INPUTS
Three TTL level digital inputs are required for SPINX1 operation, ENABLE, PWM
and direction. The ENABLE input is active low, that is it must be pulled low to enable
analog and digital outputs. The PWM signal is active high. The PWM signal is terminated
with 220/330 ohm termination resistors for signal fidelity. The DIR input is high for CW and
low for CCW
5V POWER
The SPINX1 requires ~50 mA of 5V power for operation. This is applied to TB1 input
pins 1 and 6.
MONITOR LEDS
Monitor LEDs are provided on the PWM,ENABLE, and DIR lines. The enable LED
illuminates when ENABLE is asserted, the CW or DIR LED illuminates when the direction
is CW
ANALOG OUT
The SPINX1 provides an analog output for spindle control. The analog output is a
isolated potentiometer replacement type device. It functions like a potentiometer with SP+
being the positive end of the potentiometer, SPV being the wiper and SP- being the
negative end. The voltage on SPV pin out can be set to any voltage between SP- and
SP+. Polarity and voltage range must always be observed for proper operation. The
voltage supplied between SP+ and SP- must be between 5VDC an 15VDC with SP+
always being more positive than SP-. The analog output voltage is set by PWM from the
controller. The optimum PWM frequency is approximately 5KHz, Higher frequencies will
have lower ripple but more non-linearity, lower frequencies will have better linearity but
more ripple.
A 50% duty cycle PWM signal will result in a 50% voltage output. The voltage output
is gated by the ENABLE interface signal, and forced to = SP- when enable is not asserted
(enable is active low at the FPGA interface level).
Because the analog output is isolated, bipolar output is possible, for example with
SP+ connected to 5V and SP- connected to -5V, a +=5V analog output range is created.
In this case the PWM output must be offset so that 50% PWM is generated when a 0V
output is required. Note that if bipolar output is used, the output will be forced to SP- at
startup or when ENABLE is false.
