Illinois Tool Works IJ300, Руководство по эксплуатации

Страница: 99 / 125

Controller
Appendix D: Performance Parameters
5760-121 Operations Manual Rev B Page 89 of 115
Performance Parameters of an Integrated Valve Control-
ler
The maximum line speed of an I.V. print head is limited by the maximum frequency of the
solenoid, which is 1000 Hz. The following steps will determine the operating frequency of
the solenoids in the application. The graph on the following page can also be used to deter-
mine the maximum print resolution for a given line speed.
1. Determine the values for:
•
Line speed in feet per minute: If a tachometer is not available, the line speed can be
estimated by measuring the conveyor belt and using a stop watch to time one complete
revolution of the belt. For example, a 20-foot, 7-inch conveyor belt takes 34 seconds to
make a complete revolution. Divide 60 seconds by the number of seconds per revolu-
tion (34 in this case). Multiply the resulting number by the length of the belt (21 feet in
this example; always round up to the next foot for this calculation). The answer is 37
feet per minute (60/34 x 21 = 37).
• Print resolution in dots per inch (dpi): Print resolution is selected through the software.
This setting is measured in dots per inch; a setting of 4 denotes 4 dots, or print col-
umns, per inch. Resolution can be set from 4 to 25 dpi.
2. The operating frequency of the solenoids can be determined with these two parameters
by following the next two steps:
• Determine the line speed in inches per second. Divide the line speed in feet per minute
by 5 to get inches per second. A line speed of 200 feet per minute is equal to 40 inches
per second (200/5 = 40).
• Multiply the number of inches per second by the dpi setting to determine the solenoid
operating frequency in Hz (cycles per second). Printing at 25 dpi, at a line speed of 40
inches per second, would result in a frequency of 1000 Hz (40 x 25 = 1000).
The operating frequency of an I.V. print head must be less than or equal to 1000 Hz. If it
exceeds 1000 Hz, the print head will have reliability and print quality problems. In such a
case, the best solution is to decrease the print resolution, which will decrease the operating
frequency.
To determine the maximum print resolution for a given conveyor, divide 1000 by the con-
veyor speed in inches per second. Using the previous example, 1000 divided by 40 inches
per second equals 25 dpi maximum print resolution. Even if a higher resolution is desired,
the I.V. print head is not capable of it without encountering performance and reliability prob-
lems.