Daisy-Chained Digital Thermometer

It depends on the sensor type and cable length. With 1‑Wire sensors like the DS18B20, a single bus often handles up to 100 nodes over a few hundred meters before you need a line driver. In practice, we’ve done 60-point chains at 1‑meter spacing for a 60‑m section with no data loss. If you need more points or longer runs, we split the bus or add repeaters. Better to describe your project and we’ll suggest a topology that keeps data reliable.

Not necessarily special, but it does need to speak the right protocol—most use 1‑Wire. Kingmach loggers like the KM‑101 have a dedicated 1‑Wire port and scan the bus automatically. You can also use a Raspberry Pi or an Arduino with a USB adapter; we supply example Python scripts for that. The key is ensuring the logger can provide strong pull‑up voltage and handle the bus capacitance of a long chain.

Since it’s a digital parallel bus, a dead node can pull down the whole chain if it shorts. But our chains include isolation circuitry at each node to prevent that. If a sensor just stops responding, the logger can skip it and continue polling the rest. In the field, you’d replace that section during next maintenance. We recommend keeping a few spare sensors on hand.

Technically yes, if the humidity sensor shares the same 1‑Wire or RS‑485 protocol. But in practice, mixing adds firmware complexity and can slow down the polling cycle. Most clients keep separate chains for temperature and other parameters. We’ve built combined strings before, e.g., with a voltage-output humidity chip at the same physical node, but it’s not a standard catalog item—it would be a custom project.

The individual sensors come factory‑calibrated, but over time you might want to verify. For in‑situ checks, we suggest lowering a reference probe alongside the chain in a standpipe and comparing readings at a couple of stable temperatures. If an offset is found, you can apply correction factors in the logger software. Full recalibration of the chain involves pulling it out and sending it back, which is rarely needed outside of high‑precision labs.