Electro Cam PS-6144 Series - Manual (Page 63)

4-5 Speed Compensation
Leading Trailing Speed Comp (Cont’d)
Once the second pair of setpoints is established, calculate separate leading and trailing
edge speed comp values as shown in Figure 25.
Since the new speed compensation value will affect the ON and OFF setpoints already
programmed, you will need to start the line one more time and, at a constant speed,
adjust the ON and OFF setpoints for proper gluing. Once set, vary the line speed to
confirm that the speed compensation values are accurately adjusting the setpoints over
the operating speed range.
Figure 25—Example for Calculating Leading and Trailing Edge
RPM Glue On Glue Off Difference
1st Line Speed: 200 73
°
156
°
83
°
2nd Line Speed: 680 49
°
144
°
95
°
Note that the length of the pulse is 83
°
at 200 RPM, and 95
°
at 680 RPM. This means
that the leading and trailing edges require different speed compensation values.
Leading Edge: Difference in Position: 73
°
- 49
°
= 24
°
Difference in Speed: 680 RPM - 200 RPM = 480 RPM
Speed Compensation Value: Divide difference in position by difference in speed:
24
°
/480 RPM = 0.05
°
per 1 RPM
Since a shaft at 1 RPM rotates 0.006
°
/msec (see page 4-2), this shaft would require
(0.05/0.006), or 8.3 msec to rotate 0.05
°
. The speed compensation value is 8.3.
Trailing Edge: Difference in Position: 156
°
- 144
°
= 12
°
Difference in Speed: 680 RPM - 200 RPM = 480 RPM
Speed Compensation Value: Divide difference in position by difference in speed:
12
°
/480 RPM = 0.025
°
/1 RPM
Since a shaft at 1 RPM rotates 0.006
°
/msec (see page 4-2), this shaft would require
(0.025/0.006), or 4.2 msec to rotate 0.05
°
. The speed compensation value is 4.2.