The Druck sensor employs a micro-machined silicon diaphragm into which the strain elements are implanted using semiconductor fabrication techniques. Unlike metal diaphragms, silicon's crystal structure is perfectly elastic, so the sensor is essentially free of pressure hysteresis. Autonomous Sampling allows sampling at pre-programmed intervals, and can be set up to start at a future time and date. SBE 39 continuously samples, and does not power off between samples. Time between samples varies from 0.80 to 1.50 seconds, depending on data format.
Optional pressure adds two bytes per sample.
Using a lithium battery, the SBE 39 can acquire and store more than 150,000 samples of T, P, and time. Because of the very low power consumption when not actually sampling, deployments of three years or more are possible. Paroscientific Digiquartz sensors that trace to Paroscientific's pressure standard. Other configurations vary slightly. Click the icon to download the print version of the specification sheet in Adobe Acrobat .pdf format.