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DIN rails, I2C, making multiple connections to single pins
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

DIN rails, I2C, making multiple connections to single pins

by colin_young on Mon Jun 07, 2021 1:18 pm

I'm building out my project with DIN rails for mounting and I am trying to find a simple and tidy way to make the multiple connections required for the I2C bus. I can't find a ready-made solution for DIN rail mounting and the closest I've found is the SparkFun (https://www.adafruit.com/product/4688) hat, but the problem with that is I'm also using the DIN Rail 2x20 IDC to Terminal Block Adapter Breakout (https://www.adafruit.com/product/4437) and cable. If I understand correctly, the hat would block the cable.

I don't want to stick multiple wires into a single terminal block connection, nor do I want to splice wires together. Both are just asking for trouble when you start expanding and need to add additional devices, and result in, IMHO, a bit of a mess (I'm expecting to have > 4 I2C devices ultimately).

The latest solution I've hit on is to use something like these distribution blocks: https://www.phoenixcontact.com/online/p ... 164326fd22. They are reasonably priced, come in all the required colors and will allow me to keep my wiring neat and tidy. Does anyone have any experience with creating an I2C bus in a similar manner? Are there any pitfalls or design considerations I need to keep in mind?

Is it just that once somebody starts using DIN rails they are probably already dealing with more traditional industrial supply houses, and will likely gravitate to the proposed solution? Or am I just a weirdo who is overly obsessed with keeping the wiring neat? Maybe don't answer that last one...

colin_young
 
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Re: DIN rails, I2C, making multiple connections to single pi

by adafruit_support_bill on Mon Jun 07, 2021 2:44 pm

Those distribution blocks should work.

The main concerns with i2c bus wiring is capacitance and noise. To minimize capacitance, you want to keep the total bus length (the sum of the length of all branches) short. To minimize noise in noisy environments, you may want to use twisted pair or shielding.

adafruit_support_bill
 
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Re: DIN rails, I2C, making multiple connections to single pi

by colin_young on Mon Jun 07, 2021 5:02 pm

Thanks! I've just ordered some and will report back with my impressions.

It would be nice to see Adafruit carrying distribution blocks. They are an elegant solution for when you want to build something that can be expanded or reconfigured easily, but want something a little more permanent than a breadboard.

colin_young
 
Posts: 15
Joined: Thu Oct 31, 2013 2:28 pm

Re: DIN rails, I2C, making multiple connections to single pi

by adafruit_support_bill on Mon Jun 07, 2021 5:09 pm

Thank you for the suggestion. I will forward that to our products team.

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Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.