Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 399)

Application Examples • Auger Dispensing Application 377
Publication 1398-PM601A-EN-P — October 2000
APPENDIXES
Auger Dispensing Application
Description
In auger dispensing machinery, high performance motion control systems are essential to meet the
demands of the application. Since the material being packaged varies in consistency, Allen-Bradley
products enable machine builders to provide systems that can adapt readily to changes in packaging
sizes and fill rates. Changes are easily made by operator keypad entries to the ULTRA Plus or IQ-Series
operator terminal, or by commands sent from a host computer. The conveyor and auger are driven by S-
Series or F-Series brushless motors and controlled by ULTRA Plus or IQ-Series Positioning Drive
Modules. The weight of the product being packaged is accurately controlled with the ULTRA Plus or
ULTRA Plus or IQ-Series Positioning Drive Module by monitoring an analog output signal from a load
cell. The signal is proportional to the product weight during the fill cycle. An alternative technique is to
move the auger a distance that is proportional to product weight. Coordination of two axis control is
accomplished by I/O handshaking between two ULTRA Plus or IQ-Series Positioning Drive Modules.
Advantages of Servo System
•
Less waste, higher profits.
• Accurate control of the fill process by an integrated system.
• Operator terminal provides quick setup for changes in packaging process.
• No mechanical changeovers for new production runs.
• Easily interfaces with machine controls such as PLCs or host computers.
• Clutch brake mechanisms and pulley systems are eliminated which means less maintenance.
• Brushless systems provide long life and less down time.
• Precise packaging means better quality control.
Mechanics
Sizing the servo motor and positioning drive module is important for system performance. Ideally a
direct drive system (motor to load) with a zero backlash coupling is recommended. If this is not possible
due to excessive inertia mismatch between the motor and load, the use of a higher inertia motor (F-
Series) and/or a minimal backlash gearbox is recommended. If pulleys are used, timing belts with an
HTD tooth profile or belts with similar performance characteristics are suggested.
Due to the density of products being dispensed by the auger, speed becomes an important factor. Certain
products become compressed at various speeds depending on the pitch of the auger and the size of the
drip washer. This causes friction to build up, possibly overloading the drive, and therefore needs consid-
eration when sizing and designing the system. With this in mind, an operator can enter a speed or accel-
eration variable into the Allen-Bradley operator terminal when packaging a different product.
Interfacing
The ULTRA Plus or IQ controller provides excellent flexibility for interfacing to machine controls
whether it be a host computer or PLC sending ASCII commands to the serial port, a PLC controller
using 24 VDC opto-isolated inputs and outputs, or sensors interfacing directly to the ULTRA Plus or IQ
digital and analog I/O connections.
The program example in this application illustrates the use of the analog input from a load cell to moni-
tor the weight of the package during the filling operation. As the bag nears the specified weight, the fill
is finished with a trickle feed. Once the fill cycle is complete, an output turns on to signal the sealing
operation to begin. The ULTRA Plus or IQ then waits for a bag fill and seal complete signal before
instructing the conveyor axis to index until the next product package is detected.