// Demo on how to identify and read multiple DS18B20 connected to the same bus. // Parasitic power is not used in this example. // This program is based on the sample code from Maxim/Dallas application // note 162 (http://www.maxim-ic.com/app-notes/index.mvp/id/162). Program output should look like this: *** Test with multiple DS18B20 *** Memory allocated for 20 devices. Scanning for devices... ROM CODE =62:00:00:01:CB:25:CA:28 1 ROM CODE =B6:00:00:01:CB:1B:9E:28 2 ROM CODE =66:00:00:01:CB:28:59:28 3 3 devices found. Scanning completed. Temp: 022.6875 Device: 000001CB25CA 001 Temp: 022.6875 Device: 000001CB1B9E 002 Temp: 027.6250 Device: 000001CB2859 003 Temp: 022.6250 Device: 000001CB25CA 001 Temp: 022.6875 Device: 000001CB1B9E 002 Temp: 025.3125 Device: 000001CB2859 003 Temp: 022.8125 Device: 000001CB25CA 001 Temp: 024.1875 Device: 000001CB1B9E 002 Temp: 023.7500 Device: 000001CB2859 003
Diff: main.cpp
- Revision:
- 7:cf5affdab535
- Parent:
- 4:6ade7fcb2925
--- a/main.cpp Thu Jan 28 09:16:06 2016 +0000 +++ b/main.cpp Thu Jan 28 09:21:44 2016 +0000 @@ -14,7 +14,8 @@ // ROM CODE =62:00:00:01:CB:25:CA:28 1 // ROM CODE =B6:00:00:01:CB:1B:9E:28 2 // ROM CODE =66:00:00:01:CB:28:59:28 3 -// 3 devices found. Scanning completed. +// 3 devices found. +// Scanning completed. // Temp: 022.6875 Device: 000001CB25CA 001 // Temp: 022.6875 Device: 000001CB1B9E 002 // Temp: 027.6250 Device: 000001CB2859 003 @@ -27,7 +28,8 @@ ////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////// // I have found that adding a small capacitor (100 nF or so) over the supply -// lines on long cable runs significantly reduces the number of bad readings. +// lines on each device on long cable runs significantly reduces the number of +// bad readings. // If you make temperature conversions more often than every 4-5 seconds, the // device(s) will self heat and produce a higher temperature reading. //////////////////////////////////////////////////////////////////////////////