A well-tuned warehouse operation is the summation of procedures in line with established parameters and constraints. Every aspect of inventory management must be perfectly implemented to avoid disrupting production flow. Understanding that – and acknowledging that “to err is human” – the adoption of automated warehouses has sought to mitigate such error-prone factors. Automated systems require guidance in order to execute its functions precisely. Guidance entails direct communication, along with the interpretation, delegation and control of orders. The Mecalux Group’s Galileo control software may be the sidekick to the Automated Storage/Retrieval Systems, and like any right hand, its reliable presence helps get the job done.
In 1999, automation manufacturer ThyssenKrupp developed control software for automated warehouses using programmable logic controllers (PLC), independent microprocessor-based devices that control automated processes for industrial machinery. When Mecalux acquired ThyssenKrupp’s R&D department in 2005, it inherited Galileo and began developing it as an alternative to conventional PLCs, one that would enable a real-time process and incorporate a graphical programming language for PC platforms. In its nascent stages, the control software was developed based on reusable libraries (collections of data and codes used to develop software) used by all automated implements through modules. As the software developed, Galileo incorporated a model that employs a computer language based on data structures known as “objects.” This object-oriented programming applies concepts of inheritance (creating functions based on pre-existing objects) and polymorphism (the ability to create an object that has one or more forms or functions) to arrange the objects in a type of hierarchy. Employing a graphical programming language allows individual object tasks to be carried out according to their attributes within the hierarchy, so the sequence of actions is based on the active or inactive state of the object and its behavior (the manner in which data is accessed). To provide a practical display of these motions, Mecalux also incorporated a versatile operational screen, or Graphical User Interface (GUI), into Galileo that allows warehouse operators to interact with automated devices with ease.
Three Tiers for WCS
Within a Warehouse Control System (WCS), Galileo acts as a general coordinator, establishing a control hierarchy enabling AS/RS units to carry out their tasks according to the protocols established by the Warehouse Managing System (WMS). Like an air traffic controller, each object function is an individual airplane ready to take off. The WMS — such as the Mecalux Group’s EasyWMS— assigns a series of orders to Galileo, which helps it determine a take-off order (object hierarchy) and regulates the object task once they are in the air. From executing hardware operation to streamlining communication with the WMS, Galileo instructs each individual objects as to how they must carry out their tasks. Therefore, the combination of EasyWMS and Galileo commands integrate all warehouse operations through a multi-tiered function system (Fig. 1). Located on the top tier is the ERP/HOST server, which integrates the WMS and serves as the logistical hub for picking and shipment tasks to be carried out. Once orders have been issued, the second tier is reserved for WCS tasks. From this location, Galileo controls AS/RS tasks in real-time through a fieldbus – a network structure that relays protocol commands to the operation machines. The last tier corresponds to fieldbus and periphery I/O devices such as barcode scanners, as well as AS/RS devices that actually carry out the tasks ordered by the WMS. Once orders have been completed, Galileo informs the WMS of the order status and its performance.
All for One
As a comprehensive multi-tasking program, Galileo is comprised of four control applications that provide specific internal actions and their sum total encompasses all AS/RS device communication, system monitor and motion control elements. These applications are highly versatile and configurable, so end-users can customize Galileo to meet their warehouses’ unique needs. Galileo is made up of the following:
SoftPLC – This corresponds to the control program execution and functions as a Programmable Automation Controller (PAC), combining PLC features with PC-based capabilities. (Figure 2) The PC platform will order all devices within its network through a fieldbus that links the automated devices to it. A GUI console allows operators to access the different function events, monitor AS/RS performance and network connectivity, enable workflow and configure specific tasks.
Designer – From this application, the user programs machine logic at a given facility and perform the communication configuration with the hardware elements and the WMS. Designer provides a “work space” deemed the Integrated Development Environment (IDE), wherein an operator can edit and program the written text (source code) that constitutes the programming language, as well as interpret the instructions given by the WMS. As a development environment, it allows end users to configure and develop applications such as a debugger in cases when malfunctions occur (Figure 3). Designer establishes a class hierarchy, denoting what each objects’ function will be via its relationship with other objects, as well as a vertical path of function sequences. Each object will be highlighted as it carries out its function, allowing users to pinpoint malfunctions and monitor tasks.
Status Monitor – This is the Supervisory Control and Data Acquisition (SCADA) system monitor and problem diagnosis module that accounts for quality control of operations. (Figure 4) The highly customizable Status Monitor provides a visual layout that allows operators to observe the function progress and locate any malfunction that may occur. This module allows warehouse operators to interact with facility operations, and determine manual or automatic operations.
Transport agent – This module is in charge of enabling communication between the control software and the WMS. The transport agent delivers data and manages orders issued by the facility devices to the WMS, confirms the operation status and when tasks have been completed. The newest version of the Galileo software supports a TCP/IP model, which facilitates third-party network connection to the WMS.
Since its inception, the Mecalux R&D department has continuously developed innovative solutions that resulted in simplifying warehouse operations. Although Galileo is still reaching new milestones as part of its ceaseless evolution of warehouse control systems, each released version is just an additional turn of the screw on the Galileo machine. “We continue to advance,” José Luis Santiago, IT manager for Mecalux, said, “We had improved Galileo’s internal process to make it faster and now we’re updating the IDE. We want to make the interface look better for the end user.” For Mecalux, simplifying automated solutions is bestowing the material handling world greater control over its success.