Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 408)

386 Application Examples • In-line Bottle Filler
Publication 1398-PM601A-EN-P — October 2000
APPENDIXES
In-line Bottle Filler
Description
The In-line Bottle Filler is typical of a motion control application generally referred to as a flying shear.
Flying shear applications require work to be performed on a material while the material is in motion. A
flying shear control must accelerate from a stop to match the speed of the moving material at a specific
position, and then maintain synchronization of both position and velocity while the work is performed.
After the operation is completed, the tool decelerates to a stop and returns to the start or home position.
When the correct point on the moving material approaches, the process is repeated. The motion of the
flying shear occurs within a fixed distance which cannot be exceeded, so the control must accelerate,
track the material while the operation is performed, and decelerate within this distance at the maximum
machine throughput. Flying shear applications are common in a variety of industries, including filling,
cutting, punching, stamping, forming, labeling, and printing. The Allen-Bradley ULTRA Plus or IQ
Positioning Drive Module and brushless servo motor provide the capability necessary for a flying shear
control, with the flexibility of a programmable motion controller and the low maintenance of brushless
servo technology.
Advantages of a Servo System
•
Motion automatically follows machine speed so no reprogramming is necessary if the speed of the
system changes.
• The operator interface capability of the controller allows quick set-up and change-over between
different sizes and spacing.
• Accurate, repeatable digital control produces high throughput with minimum waste.
Design Considerations
Mechanics
The servo motor must produce the required torque and speed, and should match the reflected inertia of
the mechanics as closely as possible for the best dynamic response. The torque and speed needed will
vary depending on the throughput, product, and/or repeat length. A typical machine will run at a higher
throughput with a smaller repeat length, and longer repeat lengths at lower throughputs. The worst case
torque and speed required is not always at the highest machine throughput and shortest repeat length, so
the size of the servo should be based on an analysis of the range of operation of the machine. The oper-
ating environment of the motors should also be considered. Food handling applications such as the bot-
tle filler illustrated often require motors which can withstand high pressure wash down with detergents.
The bottle filler uses Allen-Bradley W-Series motors, a sealed stainless steel motor which meets IP65
and IP66 ratings.
A belt and pulley system may be more appropriate than a lead screw for a high speed application. The
pitch and other mechanics of the lead screw limit the maximum acceleration rate and velocity of the
system.
Interfacing
The ULTRA Plus or IQ controller's 24 VDC optically isolated digital I/O provides easy interfacing to
sensors and programmable logic controllers. The FILL_EN output in the program turns on to indicate
that the fill head is tracking the bottles with no relative position error and the filling operation can begin.
The FILL_CMPLT input turns on when the filling operation is complete, and the FILL_EN output is
turned off. If the fillerhead reaches the forward travel limit before completing the filling operation, the
FILL_EN output turns off, and the POS_ERR output will turn on, indicating that a positioning error has
occurred.
System Parameters
The ULTRA Plus or IQ Positioning Drive Module system parameters must be set properly for correct
operation. Two scale parameters set the number of encoder counts per unit of distance for the motor