Seems to me like the KISS principal should be applied. Keep the water temp below a temp that will cause any problems with the concrete floor. Measure the air temp in the rooms above the floor. Control zones appropriately. Why bother measuring the temperature IN the concrete at all? Isn't that just overly complex for no good reason? Who cares how hot the concrete gets if the system is designed from the start not to damage the concrete? A sensor (or two or three for redundancy) UNDER the concrete for that one requirement of seeing if it is allowing too much heat into the ground below the floor, seems to cover that one... Why measure in the concrete itself at all? Just a guarantee that eventually a sensor will fail, and won't be easy to fix. Nate -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Volker Soffel Sent: Thursday, January 29, 2009 9:43 AM To: piclist@mit.edu Subject: RE: [EE] Burying a Temperature Sensor in Concrete At 06:20 AM 1/29/2009, you wrote: >From: "Andre Abelian" > >Why do you need to put temperature sensor in concrete ? >I am just cereus? Suppose you know the temperature ? then >What are going to do with it? > >Thanks > >Andre The purpose is to measure different heating zones of a solar powered radiant floor heating system for a single family home. Area of concrete approx 4200sqft. The temperature readings are used to adjust the hot water flow through the different zones and to monitor the performance of the overall system in general (there will also be temperature sensors to monitor ground temperature (below concrete - to verify effectiveness of insulation of concrete floor to underlying ground essentially), water temperature in the entry and return loops and outside air temperature, as water temperature also needs to be a function of the temperature delta between outside and inside temperatures. So for the concrete based sensors you are looking probably at something like 20 sensors with cable runs of up to 200 ft to get to the central collecting point. best regards Volker MicroController Pros Corporation microcontrollershop.com The World's Largest Embedded Tool Selection +1-408-776-7992 Phone +1-215-243-6071 Fax -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist