Warehouse Control System Options for Conveyor and Sortation Systems

Getting optimum performance from a distribution center (DC) facility requires many different types of material handling equipment and systems to work in tandem with precise coordination. When does each conveyor need to start or stop? At what speed should sorters operate? To which lane does each carton need to be diverted? Warehouse control systems can manage all of these decisions plus many other aspects of the fulfillment system, including scanners, labelers, photo eyes, merging capabilities, performance data and more.

Each DC has its own unique combination of employee expertise, existing equipment, product mix and other factors. Identifying the right warehouse control system for any given facility means finding the right balance among cost, efficiency and compatibility. Here’s a quick overview of the leading control solutions available today. 

Programmable logic controllers (PLCs)

PLCs are relatively easy to program, typically using simple control language, rather than requiring expertise in C++ or Java coding. On the surface, the cost of PLCs often looks competitive compared with many other types of warehouse control solutions. And since they’ve been around for a while, many people in the industry have extensive know-how relating to their use and maintenance.

The primary issue with PLCs is performance. In most cases, they’re simply not capable of keeping up with the greater demands for speed and throughput that are critical to today’s DCs, especially in e-commerce fulfillment operations. Another disadvantage is their lack of flexibility and responsiveness when issues arise in the system. PLCs struggle to keep up with modern-day needs without third-party add-ons, which can lead to higher costs. And unlike more modern control systems, PLCs lack the ability to monitor the condition of equipment proactively and provide alerts before failures occur.

PC-based systems

PC-driven solutions offer more flexibility and speed than PLCs. They are the easiest for data gathering and processing and can achieve high-speed rates of up to 400 cartons per minute using advanced merge solutions. Unfortunately, these advantages come with higher hardware costs. Every device that needs to be controlled by the system must be hard-wired into a single central panel. 

In addition, programming is more complicated than with PLCs, often requiring staff with greater coding expertise. And while this centralized control architecture allows everything to be managed from one place, the failure of any part of the system has the potential to bring the entire system down.

Warehouse execution systems (WES)

These robust software solutions address the full spectrum of modern order fulfillment with diverse automation and material handling requirements. A WES also enables dynamic, real-time decision-making for order prioritization and release execution, providing smart workflow allocation based on available capacity in downstream picking zones or order-consolidation processes like put walls or unit sortation. 

While a WES is a breakthrough technology with significant potential, full systems can be cost-prohibitive for all but the largest of distribution networks and operations. Most small- and medium-sized DCs don’t consider themselves ready for a WES, preferring to look for ways to achieve throughput and operational warehouse efficiency improvements with more limited upgrades to existing systems.

Hybrid machine control

The latest OEM machine control platforms are hybrid systems designed to combine many of the advantages of the aforementioned three solutions. They provide modern, web-based, internationalized, modular and connected solutions for conveyor and sortation control. 

While the needs of any given DC may vary, machine control often can be implemented at lower capital and operational costs than other control solutions, while decreasing the cost of delivery for projects of various sizes and complexities. Hybrid systems can offer the same superior merge speed and much of the flexibility of PC-based systems, while retaining the capability to integrate with PLC-driven equipment. 

Where to get more information

You can discover more about the latest advances in hybrid machine control and learn how to get the most from your critical conveyor and sortation systems in a newly released white paper titled Next-generation Machine Controls Drive DC Performance Improvements. You’ll learn how to overcome the vulnerabilities of traditional control systems and achieve significant reliability improvements. This report also includes details of up-to-date strategies for minimizing the time and costs required for repairs and unplanned downtime. You’ll even learn how to evaluate the efficiencies of these new strategies before you implement them.

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