50
CNC System Instruction
7.2.2. System parameters
In the SETUP submenu, press [F2] key to enter system parameters setting window, as shown in Fig.7.3.
Numerator/denominator ratio of electronic gear
----
The numerator/denominator ratio of electronic gear is pulse equivalency in micron.
Numerator < 65535, denominator < 65535.
Example: if the pulse equivalency of system is 0.008mm, its numerator/denominator ratio of electronic gear = 8/1.
Electronic Gear Ratio
= Pitch of Screw Rod × 1000(360 × Subdivision Number / Stepping Angle × Drive Ratio)
The computation method( adjustment method) of electronic gear is as follows:
（
1
）
Firstly, assume an electronic gear ratio, e.., g., 8:1.
（
2
）
Control the machine to move a reference distance( the longer, the more accurate). Measure the actual travel distance and take the measured
value into the following formula:
Numerator X Actual Travel Distance
Simplify the above formula to a fraction in lowest terms.
E., g.,
assume the electronic gear ratio is 8:1 and the theoretical travel distance is 2000mm and the actual travel distance is 2651 mm.
8 X 2651 2651
Mechanical origin
----
A special point on the machine set with proximity switch. If mechanical origin is not to be used, set it to zero. Unit: mm
( or inch)
Reference point
----
It is defined as the machining origin of program and established automatically when a program is run(G92). Unit: mm( or
inch).
Reverse backlash
----
Due to reverse mechanical backlash, the system will compensate the backlash at direction change. The
backlash value is obtained by actual measurement in mm or inch.
Generally, reverse backlash is not recommended.
Line bias
----
Axial bias between scriber and cutting torch in mm or inch.
Soft positive/negative limit switch
----
The system will give an alarm when program coordinate exceeds the set soft positive/
negative limit. If it will not be used, the parameter should be set higher than actual values in mm or inch.
Fig. 7.3 System parameters setting
Denominator X Theoretical Travel Distance
1 X 2000
250
