Post by thread:[OT]: DS1820 to DS18S20

Hello All, I was hoping someone out there may have some insight into a problem I am having. Because of instability in the Dallas DS1820 temperature sensor I recently purchased the new DS18S20 to try in some of our products. The data sheet claims the devices are functionally compatible. The only difference I noticed is the temperature conversion time has increased to 750ms. The new sensors are not working. I get a temperature reading 20 degrees higher ambient. Also the TEMPMSB register is reading as 0xFF, which is incorrect for temperatures above 0. Also a slight increase in temperature at the sensor (5-10deg) sends the reading to 100 deg +!! I have already emailed tech support at Dallas. They see know reason why code written successfully for the older sensor should not work with the new (PIC16C72). Has anyone else tried the new version? Have you experienced any trouble? Any help is greatly appreciated. Thank You, Gary W Tompkins -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hello Gary, > Hello All, > > I was hoping someone out there may have some insight into a problem I > am having. > > Because of instability in the Dallas DS1820 temperature sensor I What do You mean by instability? > recently purchased the new DS18S20 to try in some of our products. The > data sheet claims the devices are functionally compatible. The only > difference I noticed is the temperature conversion time has increased > to 750ms. The new sensors are not working. I get a temperature reading Specified conversion time for the old DS1820 is also 750ms but practical tests has proved that the real conversiontime is much faster. > 20 degrees higher ambient. Also the TEMPMSB register is reading as > 0xFF, which is incorrect for temperatures above 0. Also a slight > increase in temperature at the sensor (5-10deg) sends the reading to > 100 deg +!! > > I have already emailed tech support at Dallas. They see know reason > why code written successfully for the older sensor should not work > with the new (PIC16C72). Could You tell me what those reasons are? > > Has anyone else tried the new version? Have you experienced any > trouble? Havn't Yet, but I have just ordered 1000 DS18S20 for a new product which works fine with the old DS1820. Because of delivery problems from Dallas I won't have these here until end of February so I can't try anything until then. Sure hope it won't give me any problems! > > Any help is greatly appreciated. > > Thank You, > > Gary W Tompkins > ============================== Ruben Jvnsson AB Liros Elektronik Box 9124, 200 39 Malmv, Sweden TEL INT +46 40142078 FAX INT +46 40947388 spam_OUTrubenTakeThisOuTpp.sbbs.se ============================== -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Date sent: Thu, 14 Dec 2000 13:28:28 -0500 Send reply to: pic microcontroller discussion list <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> From: Gary Tompkins <garyKILLspamATRBIOTECH.COM> Subject: [OT]: DS1820 to DS18S20 To: .....PICLISTKILLspam.....MITVMA.MIT.EDU Hello Gary, > Hello All, > > I was hoping someone out there may have some insight into a problem I > am having. > > Because of instability in the Dallas DS1820 temperature sensor I What do You mean by instability? > recently purchased the new DS18S20 to try in some of our products. The > data sheet claims the devices are functionally compatible. The only > difference I noticed is the temperature conversion time has increased > to 750ms. The new sensors are not working. I get a temperature reading Specified conversion time for the old DS1820 is also 750ms but practical tests has proved that the real conversiontime is much faster. > 20 degrees higher ambient. Also the TEMPMSB register is reading as > 0xFF, which is incorrect for temperatures above 0. Also a slight > increase in temperature at the sensor (5-10deg) sends the reading to > 100 deg +!! > > I have already emailed tech support at Dallas. They see know reason > why code written successfully for the older sensor should not work > with the new (PIC16C72). Could You tell me what those reasons are? > > Has anyone else tried the new version? Have you experienced any > trouble? Havn't Yet, but I have just ordered 1000 DS18S20 for a new product which works fine with the old DS1820. Because of delivery problems from Dallas I won't have these here until end of February so I can't try anything until then. Sure hope it won't give me any problems! > > Any help is greatly appreciated. > > Thank You, > > Gary W Tompkins > ============================== Ruben Jvnsson AB Liros Elektronik Box 9124, 200 39 Malmv, Sweden TEL INT +46 40142078 FAX INT +46 40947388 EraseMErubenspam_OUTTakeThisOuTpp.sbbs.se ============================== -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.