Availability
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.
Shop a large selection of manufacturers and product lines.
Surplus Allen Bradley, GE, Fanuc, Emerson, Eaton, Mitsubishi, Omron, and more.
Discover insightful industry knowledge
To the untrained eye, wiring a motor to an AC drive, more commonly known as a variable frequency drive, may seem like a simple job of plugging the motor in and routing the wiring to make it look clean. The length of the wires might not even be a concern, because in an ideal world with ideal resistance, it wouldn’t. The problem is that we live in a less-than-ideal world, and the rules of physics are nonnegotiable. Whether it’s traces on a PCB or wires during a motor install, the longer the connection point, the higher the resistance, heat buildup, and voltage drop. This matters more than you might expect when it comes to installing AC drives. Before getting into it, if you would like to familiarize yourself with how an AC drive works, check out this article here ! The inherent design of an AC drive is to output fast voltage pulses rather than a clean sine wave. Each time the AC drive switches, a voltage pulse travels down the motor cable to the motor. With a shorter cable, the pulse...
Choosing the right PLC is one of the most important decisions in an automation or infrastructure project. A well-designed PLC can help minimize commissioning time, reduce stability problems during long-term operation, and lower maintenance costs. In energy-intensive applications, PLCs do more than handle basic logic. They may also support energy optimization, multi-VFD coordination, system monitoring, and long-term lifecycle reliability. The system requirements should drive the PLC selection, not the brand name alone. Start by determining how many I/O points the application requires. A small machine may only need a few dozen I/O points, while a tunnel, pump station, or utility system may require hundreds or thousands across ventilation, drainage, lighting, monitoring, and safety-related equipment. In larger systems, distributed I/O, expansion capacity, remote communication, and reliable backplane or network performance become major selection factors. For applications tied into utility...
The question of whether to replace the row of pushbuttons and selector switches on the HMI eventually arises on practically every classic machine or control panel. One touchscreen rather than twenty separate devices seems like a straightforward surface-level alternative. The engineering response is far more complex. The way the operator interface is wired, how PLC logic processes inputs, how data is logged, and how alerts are displayed are some of the key changes. Everything else that comes into contact with the hardwired safety circuit must remain unchanged. The difference between a clean migration and one that results in unexplained PLC logic rewrites, or safety compliance problems mid-commissioning, is to formally distinguish between these two groups before the project begins. Before discussing what changes, it helps to be precise about what a pushbutton panel is doing at the wire level. Each pushbutton, start, stop, jog, and mode select wires a physical contact directly to a PLC...