5-3 Speed Compensation
Standard Speed Comp (cont'd)
Response Time
Suppose that in the previous example, the response time was unknown.
Unknown
To set up the machine, jog a carton through the machine and set the glue gun ON and
OFF setpoints as described earlier. Then, estimate a response time and enter it into the
controller using the SPEED COMP function described in Section 3.
Start the line and run cartons through it at a fixed line speed. Program SPEED COMP to
adjust the speed compensation value as required for proper gluing. This can be done
while the line is in motion. Once programmed, vary the line speed to confirm proper
operation at all speeds, and fine tune the SPEED COMP value if necessary.
Can’t Be Jogged?
Some machinery can’t be jogged to determine ON and OFF setpoints. To set up this
type of equipment, start the line, run cartons through it at a fixed line speed, and set the
ON and OFF setpoints as required for proper gluing. Write them down for reference in
the next step. SPEED COMP should be set to zero.
Next, increase the line speed and adjust the setpoints to restore proper gluing. You
might be tempted to enter a speed compensation value to do this. However, since the
setpoints were adjusted at the first speed with zero compensation, any change in com-
pensation value now will upset the first pair of setpoints.
Once the second pair of setpoints is established, compare them to the first pair that you
wrote down. Establish a ratio of degrees the setpoints advance versus the speed as
shown in Figure 26. Convert this ratio to response time and enter it as the speed com-
pensation value.
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 value is accurately adjusting the setpoints over
the operating speed range.
Figure 26—Example for Calculating Speed Compensation
RPM
Glue On
Glue Off
Difference
1st Line Speed:
200
73
°
156
°
83
°
2nd Line Speed:
680
49
°
132
°
83
°
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, this shaft would require (0.05/0.006), or
8.3 msec to rotate 0.05
°
. The speed compensation value is 8.3.
