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
with220/330ohm termination resistors for signalfidelity. The DIRinput is high forCW and
low for CCW
5V POWER
TheSPINX1requires~50mA of5Vpowerforoperation.Thisis appliedtoTB1input
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.
A50%dutycyclePWMsignalwillresult ina50%voltageoutput.Thevoltageoutput
is gated bytheENABLE 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.