INTRODUCTION

TOMACS is a computer software system for facility-wide operation management and automated control of bulk materials handling terminals. The purpose of the system is to increase throughput and minimize operating costs of a facility by improving the utilization of equipment, reducing multiple handling of material consignments, and eliminating accidental mixing of commodities of different quality and value.

TOMACS was developed for the Alberta Wheat Pool Vancouver (AWP) grain terminal, and connects to the MODICON 984 PLC control system via network gateways. The system's generic functional implementation and software structure allows it to be tailored for use in other materials handling terminals of widely varying sizes.

TOMACS DESCRIPTION

TOMACS (Terminal Operations Management and Control System) is a system for managing and controlling the transportation of bulk grain within a terminal facility designed to receive, process, store and ship various grades of grain in discrete batches or jobs. A job identifies the movement of a predefined quantity of commodity of a single grade, from one part of the terminal to another. The routing of grain within the facility can be aided by rule-based decision programs that determine the best source or destination of a movement, and the optimum path of movement, based on rules and strategies defined by the terminal managers. Alternatively, grain-flow routes, sources and destinations can be fully specified by the terminal operators.

Jobs are scheduled, executed and controlled in modes that are either fully automatic, based on information obtained by TOMACS in electronic form, or semi-automatic, based on interactions with terminal supervisors and control system operators. Movements of commodities are measured and fully tracked through all operations, and monitored to prevent accidental cross-contamination of processed or stored grain.

For the purposes of quantity measurement and flow coordination, a job is decomposed into sequential tasks, defining the movement of commodity between intermediate holders or buffers along the route between source and final destination. The physical flow path between holders is further decomposed into flow segments. A flow segment begins and ends at either a holder or a point of convergence or divergence of grain flow (e.g., positioning device).

Physical control of grain movements is governed at the flow segment level by TOMACS, through a high-level interface with the PLC control system. Control involves the assignment, setup, starting and stopping of physical flow segments.

Terminal Control Systems Operators monitor the operation on desktop workstations through colour graphic display windows that present multiple overview and detailed pictures of grain-flow and equipment in each operating area (receiving, cleaning, shipping, transfers). Operators control the operation mainly in relation to jobs and tasks, releasing, suspending, resuming, and completing grain flows as needed. Operational status of jobs and tasks is presented in user-friendly pop-up display windows, and all control actions are initiated by selecting visual icons or lists of options.

Receiving and shipping jobs are scheduled in advance of grain movements, based on operating assignments, shipping orders and material receipts. Cleaning jobs are generated automatically as grain is delivered into the terminal by the receiving system, based on grade assignments made during each shift by the operations supervisors. Transfer jobs are generated on demand by operations supervisors, or scheduled automatically as holding bins fill up. Shipping jobs are generated, based on loading contract information and lists of eligible source bins produced by a foreman with the aid of the TOMACS inventory query feature. Blending of grain into a shipping job is performed by manual selection of additional source bins.

Statistical analyses and summary reports are provided for job and equipment performance over shift, daily and monthly periods. These reports are generated using 4GL tools provided with the IDEA product, and are easily configurable and alterable by the owner's systems managers. In addition, free-form ad-hoc reports and queries can be generated by operations supervisors, regarding any aspect of the operation contained in the databases.

KEY FEATURES

Major features of TOMACS are:

Advance scheduling of material movements;
Supervisory control of all material handling operations;
Accurate tracking of material movements and inventory;
Cross-contamination prevention;
Automatic or semi-automatic operation of grain flows;
Adjustable operating strategies through processing priority assignments;
Rule-based decision algorithms for operation tactics;
Automatic equipment pre-emption by high priority operations;
Automatic operation schedules pre-setting of manually controlled equipment, to remove these operations from the critical time path;
Performance analysis in aid of planning and strategies;
Flexible, easy-to-use, windows-based operator interface;
Large event archive for post analysis of operation details;
Alarm management brings cause-of-fault to attention of operators;

KEY BENEFITS OF SYSTEM

Complete and up-to-date material inventory information.
Increased average terminal throughput (10-15% typical).
Decreased operating costs due to reduced re-handling of material, prevention of material cross-contamination and accidental mixes in ship-holds.
Reduced personnel costs through increased human productivity, and decreased manpower requirements.

STRUCTURE OF TOMACS

The TOMACS Application Software is layered upon two products supplied by DATAP Systems, IRIS 75000 and IDEA, which contain the structures for supervisory control and analytical applications. The TOMACS Application Software includes all tactical and strategic operation sequencing or coordination software, which operate both flexibly and responsively in real-time.

The consistent use of a generic, object-based job/task/flow processing model of materials handling operations to structure the application software and databases, has enhanced the re-usability of the TOMACS system. This model is easily expandable to include new optimization applications.

The implementation of the Alberta Wheat Pool project included considerable improvements and additions to the IRIS/IDEA infrastructure. These improvements were primarily designed to support the maintainability of the AWP system by both Sandwell and AWP personnel during system integration; coincidentally these improvements greatly enhance the re-configurability of the system.

Very little knowledge of commodity details and equipment details is embedded in the control logic of the TOMACS software, but rather is contained in the various databases and graphical displays of the system. These details are configurable by the customer's system managers through editing utilities provided with the system.

SYSTEM CONFIGURATION

The TOMACS system consists of the following components.

Digital Equipment Corp. dual VAX 6400 multi-processor servers, each equipped with 192 MB of memory, four 622 MB disk drives (two of them shadowed for data security), OpenVMS operating system.
Ethernet network using DECNET and TCP/IP protocols.
13 VAXstation 4000-VLC workstations with 16 MB memory, 121 MB internal disk, 17" or 19" Trinitron colour monitor, keyboard and mouse, VMS and DECWindows S/W, Ethernet adapter.
PLC Gateway (dual redundant): DOS based 386 PCs, and QNX operating system.
Peripheral Devices: various printers, e-net servers, VDT terminals, network communications equipment.

The software and hardware configuration are highly scaleable, and an equivalent contemporary configuration would typically be based on a range of DEC ALPHA AXP servers and AXP workstations or x-terminal/Motif server devices.