rpm sync with spindle and motor

I'm using spindle with servo motor.
the spindle rpm is increased by servo motor 3 times.
(for example, the spindle rpm is 3000 when the servo motor rpm is 1000)

now,
m3 s1000 command have my spindle rotate 3000rpm
what I want is
m3 s1000 command have my spindle rotate 1000rpm

if it's possible could you let me know how to do?

and one more question is
if I connect from encoder of the servo motor to 7i76 (A, B, Z)
Can I display rpm on pyvcp in linuxcnc by using 3 signals(A, B, Z) which come from servo motor encoder to 7i76(with 5i25)
(servo motor have 2048 pulse/1turn)

thanks,
Byoungil Choi

if you are using the 7I76 analog spindle interface you would just multiply the
spindle scale by three.

if your config was generated by pncconf,
change N to 3N in your ini file:

#********************
# Spindle
#********************
[SPINDLE_9]
OUTPUT_SCALE = N
OUTPUT_MIN_LIMIT = 0.0
OUTPUT_MAX_LIMIT = N


And yes you can use the encoder to read spindle speed
(you will have to set the encoder scale correctly)