
9
FANUC Series 16i /18i -MA
Spindle electronic gear box
S
ecifications
EDT. DATE DESIG. DESCRIPTION PAGE /19
A – 77833E
NO.
TITLE
NEWLY
1999.July.28
01
2.5 Synchronous ratio
The synchronous ratio of the Spindle EGB control is internally represented using a
fraction. The fraction is calculated from T and L command in G81 block and the number
of position detector pulses per rotation about the tool and the workpiece axis (parameter
setting).
Synchronous ratio :
1
2
K
K
=
T
L
A
B
×
L : Hob threads
T : Number of teeth of the work
A : Number of position detector pulses per revolution about the tool axis
(Parameter No.7772)
B : Number of position detector pulses per revolution about the workpiece axis
(Parameter No.7773)
This synchronous ratio is reduced to the lowest term, and it has the following limit.
-32767 < K2 < 32767
1 < K1 < 65535
When K2 or K1 is out of this range, P/S alarm (No.181) occurs.
The values of K2 and K1 are set to the parameter No.4387 and No.4388 automatically
when G81 is specified. If T is not specified in G81 block, P/S alarm (No.181) occurs. If L
is not specified in G81 block, the synchronous ratio is calculated as L = 1.