An Ode to Industrial Standards

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. If you just want to push the data from a sensor to the internet, it’s a lot of extra equipment. Not to mention, that bulky-yet-reliable equipment? It often comes with a hefty price tag.

A few weeks ago, we released a reference design that skips a lot of these steps. In fact, all that’s required is a piece of hardware that has an RS-485 interface and an internet connection. In our case, it’s the nRF9160 plus some breakout boards, talking back to the Golioth Cloud. We showcased the Modbus Vibration Monitor Reference Design using a motor monitoring sensor, but now we’re able to swap out that sensor for any other Modbus (RTU) sensor. That’s the power of an industrial standard. Now that we have a connected, embedded device talking Modbus, the rest is just firmware updates. Oh yeah, Golioth does that part too!

Modbus is far from the only standard out there. It benefits from wide ranging, long time adoption due to the fact that it’s openly published, royalty free, and easy to implement. But there are other sensors and end devices running things like EtherCAT, CAN, PROFIBUS, HART, BACnet, Foundation Fieldbus, DeviceNet, and more. Once you start to think of these protocols and standards as a common language among end devices, the power of a common platform like Golioth hardware, firmware, and Cloud software really starts to emerge. Let us know if you see a need for any of these other standards in your projects!

* somewhere an engineer is saying, “you think that’s old, check out this other industrial standard!”

A proper Ode

Oh, Modbus, protocol of precision, thou art,
In the realm of data, thou playest a crucial part.
With thy structure elegant, and format clear,
Thou bringest connectivity far and near.

From the industrial floors to automation’s lair,
Thy presence is felt, ubiquitous and fair.
In the language of ones and zeros, thou speak,
Binding machines together, strong and sleek.

With thy bit twiddling dance, thou dost choreograph,
In the symphony of automation, thou art the staff.
Thy messages traverse through wires unseen,
Connecting devices, a diligent machine.

In the world of SCADA, thou never are flawed,
Transmitting signals at 9600 baud.
Reliable, robust, thy virtues abound,
In the realm of control, thy praises resound.

Oh, Modbus, thou art a beacon bright,
Guiding engineers through the darkest night.
With thy registers and coils, thou dost empower,
Enabling systems to function by the hour.

Though newer protocols may rise and fall,
Thy legacy, Modbus, shall stand tall.
For in the annals of technology’s lore,
Thy name shall echo forevermore.

So here’s to thee, Modbus, noble and true,
In the world of automation, we honor you.
For without thy steadfast hand to guide,
The wheels of progress would surely slide.