Wine technologies Ltd (or Winetec) are a NZ/US Based company who specialise in SCADA and HMI systems for Wineries worldwide, their main product is called the VinWizard system and incorporates many self designed innovations one of which is the multi-level probe.
David approached me in 2007 about the possibility of making this system, he had a good grasp on how his customers wanted it to work and asked me about the feasibility of designing the electronics and firmware to allow full MODBUS control from his PLC’s.
Without giving too much away (as the system again was built for resale and not open source) it was another case of very simple and reliable electronics, which needed to be fully potted and waterproof, must be ultra low power (from 24V) to prevent any self heating (for both reliability and not to influence the sensor reading at all) Lastly it had to be simple to wire up, it was never going to work if we had a separate wire for each temperature sensor, the sensors are therefore daisy chained on a single data wire. The firmware for the system exposed a set of MODBUS registers and had to be self-configuring to the number of probes attached, this, some real SMD miniaturization and some very clever integration by David was the secret source that brought the project together.
The system is now working successfully and more information can be got through the vinwizard web site above