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by frankpc
Mon Apr 08, 2019 11:47 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

Thanks. Yes, the valves would turn off if they were on in the event of a power outage. We seldom lose power, but I figure we'll be on vacation, lose power here, then have the sprinklers turn on for a week or so. Glad to hear the pi can be programmed to prevent that. I'll get a pi hooked up. Thanks f...
by frankpc
Mon Apr 08, 2019 5:31 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

The 1wire driver chip takes care of any signal contention when multiple sensors are responding.... and causing grey hairs. :) First of all, grey hairs are all I have and to get more would be a good thing. :-) I know from reading your posts of the success you have had that using the 1-wire driver ch...
by frankpc
Sat Apr 06, 2019 1:10 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

I'm definitely not the right guy to answer this question. But, from everything I've read, you can't have two sensors equal-distant from the master. I would like to better understand that. But, it seems the sensor's initial response to the master could be related to the time delay caused by the dista...
by frankpc
Sat Mar 30, 2019 2:16 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

Thank you for the responses guys. All my multi-sensor tests were done in a star-topology arrangement, which did not work. And the tests were done with a CAI webcontrol board master, which uses integrated firmware. So there is no way to program or customize the master. I read the Maxim document and f...
by frankpc
Fri Mar 29, 2019 1:55 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

I haven't found an explanation of the initialization process that occurs when the master hasn't learned what sensors are on the bus. I don't understand where the "randomness" would be created to ensure each sensor has a chance to report its online status and to include its address. I have tried to g...
by frankpc
Thu Mar 28, 2019 9:53 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

I've reviewed all of your posts on this subject. All of it makes sense. I have one question... I don't understand how the pi or in my case a CAI webcontrol board, gets the addresses of each sensor initially. In my case, looking back, I realize all of my tests with multiple sensors were conducted wit...
by frankpc
Sun Mar 24, 2019 5:29 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 44037

Re: DS18B20 Max Distance

@JohnsUPS, Thank you for all your hard work on this and for providing the ideas you have to make it work. I've been battling this myself. Today, I doubled up on conductors per your advice. And it seems things may be working better. I am not using a driver chip, nor am I using a RPi. (yet). I ended u...

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