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How many one wire devices does it support

17 Views - Created 6 days ago

6 days ago

Posted by:
mikeb

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I'm currently trying to run my Solar heating using a raspberry Pi. I've connected 5 DS18B20 devices but the whole system is so unreliable which is not good for solar heating. I thought it was my system but it seems this is not uncommon. One fix is to run the 3.3V from a GPOI so it can be reset. Hmmmm.

Q1: So I was looking at this device to use instead but no where does it say, that I can find, how many devices you can connect. I presume one physical connector is not the limit and you can simply connect many to this port in parallel, daisy chain etc?

Q2: The pi allows you to add multiple dt_overlays allowing you to run multiple circuits in case you have long runs etc. Does this device allow you to have the same arrangement? I presume the solder connection and the two connectors (if one was added) would all be on the same circuit. So the only way to achive the same is to add a second board?

Regards,

Mike

6 days ago

Posted by:
andrew

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Location:
United Kingdom

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Hello Mike

The maximum number of devices you can connect to the 1 Wire bus is dependent on several factors including cable length, the type of devices connected and any external interference on the network.  Maxim has a good application note on creating 1 Wire networks, I would recommend reading through that to get a better understanding of how to set up your devices.

Each 1 Wire Pi Plus only contains a single 1 Wire bus but you can stack up to four 1 Wire Pi Plus boards on a single Raspberry Pi.  Each one will need to have a different I2C address set using the solder jumpers on the board.  The product page for the 1 Wire Pi Plus includes instructions on setting the I2C address.

The two RJ12 connectors on the 1 Wire Pi Plus are connected to the same circuit.  We added two positions for the connector so you can alternate between the connector positions when several boards on the Raspberry Pi, otherwise they are slightly too tall to stack correctly.

AB Electronics UK Tech Support

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