High-tech grain handling
June 01, 1994
by Teresa Acklin
Part one of two: how computer-based automation can streamline elevator operations and boost profits
This article is based on a paper by Jon E. Walker Jr., vice-president of sales for Advanced Control Technology, Inc., Albany, Oregon, U.S.; and Heidi Holderman, control systems project engineer for Advanced Control Technology. The paper was first presented at the 1993 International Technical Conference and Exposition of the Grain Elevator and Processing Society.
Imagine being able to automate your elevator so you can control it entirely from a computer terminal within the control room. Sound impossible? Through proper design and well-defined, structured implementation of automated systems, it is possible not only to operate in this fashion, but to operate with increased profit margins.
Automation can be applied to all elevators, from small country facilities to larger export terminals. Although each elevator may operate differently, these automation ideas are consistent and can be applied to all elevator operations without major modifications.
Reasons for automation
The main objective in elevator automation is to increase profit margins. But automation offers at least four other benefits improved safety, improved quality, increased productivity and increased reliability that in turn can boost profitability. When an elevator operates safely without hazard to its personnel and does so while delivering a high-quality product to the customer in a productive and reliable manner, everyone benefits.
The first reason for automation, to improve safety, is probably the most important to your operating staff. Every elevator must deal with the hidden safety-related costs stemming from manual operating requirements. Unfortunately, every elevator has experienced a lost-time accident that resulted not only in harm to an employe, but medical insurance and production costs to the elevator.
Automation can eliminate many of the potential hazards inherent in manual operations, including gate opening and closing, distributor positioning, tripper operations and bin level measurement. Moving these functions into the control room through automation reduces the frequency of operator exposure to potentially hazardous situations; and any improvements in safety for the elevator's work force will reduce costs and, therefore, increase profits.
The second reason for automation is to improve quality control, as automation allows for better monitoring and regulation of control and information functions. Consistency in control functions such as blending increases the quality of delivered grain. Automation of information functions such as inventory processing decreases product misidentification, again raising the quality of delivered grain.
With automation, an elevator can increase quality through more consistent control and more reliable recordkeeping, resulting in increased profits.
The third reason for automation is to increase productivity. This is where most of the profit margin is realized. By automating an elevator, productivity gains arise from improved diagnostics and reduced staffing requirements.
An automated elevator provides improved system diagnostics through real-time equipment feedback, allowing a potentially detrimental situation to be corrected in a timely and cost-effective manner. An automated elevator also reduces operator interaction, supervision and paperwork, which cuts manpower costs.
By automatically setting up equipment flowpaths, the interaction between operator and elevator control is minimized, thus reducing both supervisory and paperwork tasks.
The fourth reason for automation is to increase reliability through the use of state-of-the-art equipment with proven technology.
This technology offers consistent operations control and improved information flow, which reduces downtime and permits predictable, planned maintenance. By reducing unforeseen maintenance and downtime, operating costs will be cut and profit margins will improve.
Automation systems are abundant and continue to increase in diversity and complexity as the demand for quality and productivity grows. Automation can be as simple as updating and replacing existing hardware or as complex as implementing an integrated computer-based system.
A computer-based system consists of three foundation components: programmable logic controllers (PLCs), color graphic workstations and information control workstations. These components can be implemented independently or as an integrated system.
The foundation components are fundamental to the success of the automation project, and plant-level control is best developed using PLC systems. These systems provide electronic methods for remote control and feedback reporting of equipment status.
The operator controls the PLC system through the color graphic workstation, which eliminates the need for the hardwired push-button control panel. The color graphic workstation enhances functionality and ease of operation.
Information control workstations make up the operational data processing element of the automation system. These workstations communicate with the corporate host computer system to exchange contract data and provide real-time inventory updating.
The first and most basic component for an automated elevator is the PLC system, which uses PLCs to control and operate equipment. PLCs are relay logic microprocessors that allow almost any device to be controlled electronically through digital and analog inputs and outputs.
Many in the grain industry have been exposed to PLCs through selective implementations, such as dust or cleaning systems. Today's PLCs are recognized as the industry standard for cost-effective, reliable control of elevator equipment such as conveyors, gates, belts, tripper and chutes.
Easily programmed in languages familiar to most elevator electricians, PLCs provide relay replacement and interlocking control to allow for equipment sequencing. This creates a predictable environment that can lead to improved elevator operations.
A PLC system can be implemented using existing manual push-button panels and, without any further automation, will increase an elevator's profitability. But because today's PLC systems can use high-speed local area network communications, automation can be further expanded. This leads us to the second foundation component, color graphic operator interface systems.
Networking the PLC system to the color graphic interface system eliminates the need for push-buttons, thumb-wheels, toggle switches, lights and analog displays. The information can be controlled and monitored graphically on a computer using many powerful and configurable software products.
The color graphic workstation provides a graphic image of grain flows and equipment status for elevator operators and inspection personnel. It also improves efficiency by providing centralized control of equipment that previously was controlled remotely in the elevator or from a hardwired control panel.
With the computer-based interface, inadvertent control mistakes can be eliminated. By using security passwords, only authorized personnel will be allowed to initiate control actions. These passwords can be segregated by levels of responsibility, therefore clearly defining the roles of operating personnel.
The third foundation component is the information system, which expands on network capability and adds the potential of multi-tasking operating systems. The information system allows for a paperless transfer of operational information from the PLCs through the color graphic workstation to the information system and then on to the corporate host computer; the host computer also can initiate the paperless transfer.
Data originating from the host computer system, such as rail car pre-advice, can be used by the information system to make operational decisions. These decisions then can be initiated by the color graphic workstation and carried out by the PLC control system.
This final element in the automation equation can encompass many aspects of the elevator information flow. Some of these aspects include logistics for grain loading and unloading, grading information, storage bin sounding systems and computerized bulk weighing systems.
The information system's ability to combine different data sources into a relational database creates a real-time inventory system, which can be essential for elevator operations in today's competitive market.
With one or all of the foundation components in place, other automation components also are available. These include auxiliary features such as alarming and maintenance systems, as well as automatic pathing systems.
Using the PLC system and the color graphic workstation as a platform, an alarming system can be developed to make an operator aware of failed or malfunctioning equipment. With this system, malfunctions can be corrected before the equipment fails.
If equipment has failed, the alarming system can determine the cause by monitoring such devices as the motor circuit breaker, thermal overload, winding and bearing temperatures, belt alignment and speed switches. This allows the operator to identify the problem quickly, which reduces downtime.
A maintenance system also can help reduce both downtime and maintenance costs. By monitoring motor runtime hours and related equipment operating conditions, the system can generate part maintenance request forms automatically. A well-organized maintenance database can generate forms containing all the information needed, including part number, manufacturer, model number, motor size, last maintenance date, location and any notes of interest.
Another auxiliary component is an automatic pathing system, which can be implemented if the total complement of foundation components are integrated. With the pathing system, pre-advice information can be used from the system to organize storage bin assignments.
Unload lists and barge lineups can be used to set up pathing and routing of material. Automatic sequencing of equipment can be controlled from a single keyboard selection on the color graphic workstation. All interlocks are maintained in the PLC to prevent any unwanted control actions. The system streamlines operator interaction, leading to increased productivity and greater profits.