Electro Cam PL-1746 Series - Manual (Page 94)

5-3 Speed Compensation
Standard Speed Compensation (cont’d)
When setting speed compensation on a system where zero-speed pulses have
been established, always adjust the speed compensation value. Do not adjust
the individual pulse edges!
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 edges as described earlier. Then, estimate a response time and enter it into the
controller using the SPEED COMP function described in Chapter 4.
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 edges. To set up this type
of equipment, set speed comp to zero, start the line, run cartons through it at a fixed line
speed, and set the ON and OFF edges as required for proper gluing. Write them down
for reference in the next step.
Next, increase the line speed and adjust the edges to restore proper gluing. You might
be tempted to enter a speed compensation value to do this. However, since the edges
were adjusted at the first speed with zero compensation, any change in compensation
value now will upset the first pair of edges.
Once the second pair of edges is established, compare them to the first pair that you
wrote down. Establish a ratio of degrees the edges advance versus the speed as shown
in the example below. Convert this ratio to response time and enter it as the speed
compensation value.
Since the new speed compensation value will affect the ON and OFF edges already
programmed, you will need to start the line one more time and, at a constant speed,
adjust the ON and OFF edges for proper gluing. Once set, vary the line speed to
confirm that the speed compensation value is accurately adjusting the edges over the
operating speed range.
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
°
. So the correct speed compensation value to enter is 8.3.