
B-63003EN-2/01 Chapter 2 Configuring the 16i/18i/21i 2 - 15
2
Example - Determining Settings for a Semi-Closed Feedback Loop
Figure 2-4 illustrates how a motor could be connected to the screw. We have a 1,000,000 count
built-in encoder, a 10mm screw pitch, and a 2:1 gearbox.
1,000,000 pulses/rev
10mm screw pitch
200 teeth
100 teeth
}
2:1 gearbox
Figure 2 - 4. Diagram of the setup used in this example
Procedure for Calculating CMR and
N
M
1
.
Look up the detection unit and flip it over to get the pulse count.
2
.
Look up the LCI and flip it over.
3
.
Plug the previous two values into eq. 2 and calculate CMR.
4
.
Determine what kind of feedback you have and its resolution.
5
.
Find out the mechanics of the system ! gear ratios, screw pitches, etc.
6. Use the system mechanics to calculate
mm
srevolution
.
7. Multiply the result from step 6 with the motor resolution from step 4.
8
.
Plug in values from steps 1 and 7 into eq. 3 to calculate
N
M