The temperature measurement is made with a DS-2438Z. The device is not calibrated, but empirical data shows it to be accurate within a few degrees of actual, with an operating range of ‚Äď40 to +85°C. Because the sensing device is partially enclosed and mounted to the PCB, the response time to temperature changes will relatively slow. Care should be taken not to place the sensor in direct sunlight, as the radiant heat will be partially trapped inside the enclosure and cause readings higher than ambient.
MultiSensors, like all 1-Wire slaves, can operate on ‚Äúparasitic‚ÄĚ power. That is, they use the power contained in data signal of the 1-Wire bus, with a capacitor to sustain them during the zeros. Unlike most other 1-Wire devices, MultiSensors have an AUX jumper. This jumper connects the Vcc line on the sensor directly to the power source of the serial port (via the master Link), thus providing a constant Vcc to the sensor independent of what the line signal doing. The AUX jumper is set to provide Vcc when shipped from the factory.