An Ode to Industrial Standards

Originally published at: An Ode to Industrial Standards - Golioth

This is an excerpt from our bi-monthly newsletter. You can sign up for future newsletters here. I love old* industrial standards like Modbus. It was created in 1979 and widely adopted by machine makers since then. It has survived and continues to be used because old industrial machinery just doesn’t seem to die. If the equipment doesn’t die and the equipment runs an industrial standard, by the transitive property, that standard isn’t going anywhere. In 2024 (a short 45 years after the inception of Modbus), there continues to be equipment out in the field that uses the standard. Some of that equipment is brand new, too! Technically, Modbus is a communications protocol (OSI layer 7). But by default it doesn’t connect to the broader internet, it connects to other machines. For “Modbus RTU”, this involves hooking machines together using RS-485, another standard, but one for the data link layer (OSI layer 2). It is hardened against interference for noisy industrial environments. As a result, it’s reliable. My experience in the industrial sector has taught me that more than anything else, reliability is key. It’s the same reason that 4-20 mA sensors are used, and the bulkiness of the electronics is normally not an issue. If a circuit requires a massive protection diode? Well, make the enclosure bigger! It needs to be reliable. Normally you’d have a Modbus sensor talking back to an industrial controller like a PLC. This was the localized control that allows fast action on the factory floor (“the temperature sensor is too high, turn down the heating element”, etc). As the times modernized, so did the connectivity options on the PLCs. But in many cases, it’s overkill.…