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Millions of parts are available for same-day shipping and next-day delivery.
Save money on downtime with the most trusted leading experts in automation replacement and repair.
Millions of parts are available for same-day shipping and next-day delivery.
45+ years of experience to help you find an ideal replacement or repair solution.
We stand behind our quality by offering a complimentary 2-Year DO Supply Warranty on all products.
DO Supply is a global leader in replacement parts for industrial automation equipment. Our mission is to elevate the standard of expert support, speed, and reliability for your need-it-now automation replacement and repair needs. Whether it's PLCs, drives, motors, HMIs, or more, you can count on us for the best service and fastest solutions.
Shop with confidence knowing that we offer fast shipping and best-in-class customer service. Explore our large inventory of in-stock automation parts backed by the guarantee of a 2-year DO Supply Warranty.
Save money on getting your automation parts repaired for less, backed by our 2-year DO Supply Warranty. We offer quality repairs at the best prices, carried out by expert technicians.
We want to buy your industrial automation surplus equipment, including PLCs, drives, motors, HMIs, and more.
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Discover insightful industry knowledge
Unplanned downtime is one of the biggest concerns in industrial production. A single control-system failure can stop an entire production line, leading to lost material, idle equipment, missed deadlines, and costly delays. For this reason, high-uptime ControlLogix systems are designed around more than just the controller itself. Controller redundancy, resilient EtherNet/IP networks, redundant power, distributed I/O, and advanced diagnostics can all help keep a system running when something goes wrong. However, simply installing higher-end hardware does not guarantee reliability. The overall architecture still needs to reduce single points of failure and allow the system to recover quickly when a fault occurs. High-uptime control systems should be engineered to withstand single-component hardware failures while maintaining continuous operation — without interrupting data execution or process outputs. The ControlLogix platform accomplishes this through a synchronized, redundant chassis...
Distributed control systems, essential to modern industrial automation, need distinct hardware components to communicate seamlessly across large facility floors. The Programmable Logic Controller (PLC) is at the core of this system. PLCs execute control logic, process sensor and I/O data, command field devices, and exchange information with HMIs, SCADA systems, drives, remote I/O, and higher-level systems. But a PLC’s effectiveness depends on the communication networks that connect it to company databases, input/output (I/O) modules, human-machine interfaces (HMIs), and supervisory control and data acquisition (SCADA) systems. Over the last several decades, simple proprietary serial lines have given way to sophisticated, high-speed Ethernet-based protocols. Determinism, bandwidth, distance, setup complexity, and cybersecurity must all be balanced to choose the best protocol, which is seldom a simple technical task. Automation engineers must understand these trade-offs to build...
A variable frequency drive (VFD) rarely fails suddenly. Instead, before a VFD stops reliably operating a motor, it will begin to show signs of degradation, starting with symptoms like increasing fault counts, distinct noises, or thermal stress. These eventually culminate in signs of the drive’s aging internal components. If maintenance crews spot those early warnings, they may have time to install a new VFD before failure, keeping production running. A VFD’s service life is mainly controlled by two wear-limited parts with documented, temperature-dependent life expectancies: the electrolytic capacitor that forms the DC bus, and the cooling fan. Aging in both components is slow — they don’t fail on a fixed date but degrade gradually, so assessing age means understanding behavior, not just install date. ABB’s ACS550 documentation (page 67, section 4) and the ACSM1 VLT FC 302 documentation (page 4, section 2) describe this best. Electrolytic capacitors on the DC-link circuit smooth the...