EMO-R8 intermittently not seen by i2c

Merv
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EMO-R8 intermittently not seen by i2c

Postby Merv » Sat May 14, 2016 4:02 pm

Hi,
I'm running a unipi with an EMO-R8 extender, and a 1W-R4-DI4 for my home automation.
when I run
i2cdetect -y 1
I can see address 21 show up, and if it does, the evoc program web page allows me to see the relays 9 through 15 (EMO-R8) and to turn them on and off. BUT: Sometimes address 21 is not there, and I need to pull the i2c data cable from the expansion board for a few minutes, and then put it back to allow the expansion board to be seen.

What might be wrong with my setup?

Merv.
tomas_hora
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Re: EMO-R8 intermittently not seen by i2c

Postby tomas_hora » Mon May 16, 2016 7:49 am

Hello Merv,

do you have the possibility to check the cable between UniPi and Emo-R8, maybe re-rcimp it if you have the tool?
Merv
Posts: 11
Joined: Sun Feb 21, 2016 1:27 pm
Location: Ireland
Contact:

Re: EMO-R8 intermittently not seen by i2c

Postby Merv » Sun May 22, 2016 11:02 pm

Hi, I checked it visually, and checked all pins were tight with a small screwdriver, and the cable seems ok. The Data light is coming on on the EMO-R8. but it's still intermittent.... I'll bring home a Multimetre and try belling out the cable, but I think it's ok....
tomas_hora
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Posts: 298
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Re: EMO-R8 intermittently not seen by i2c

Postby tomas_hora » Mon May 23, 2016 11:49 am

It might also be caused by a ESD from a near power relay or a frequency changer... So maybe some shielding might help. Can you provide a picture of your setup?
Merv
Posts: 11
Joined: Sun Feb 21, 2016 1:27 pm
Location: Ireland
Contact:

Re: EMO-R8 intermittently not seen by i2c

Postby Merv » Tue May 24, 2016 11:03 pm

I think this may be the issue, I have it installed right beside the 12V transformer......

Appologies for the link, I used to know how to get the url of an image in Flickr, but it seems they have changed how it works...

https://www.flickr.com/photos/mervcolto ... ed-public/

Image
tomas_hora
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Re: EMO-R8 intermittently not seen by i2c

Postby tomas_hora » Wed May 25, 2016 10:03 am

Yep, the I2C bus not much resistant to the EMC. I have a few ideas:
  • shield the I2C cable with aluminium foil and lead the cable under the din rail which you use for the blue cables
  • place the EMO-R8 insted of the 1Wire hub or 1Wire relay/input board
By the way, very nice installation! :)
Merv
Posts: 11
Joined: Sun Feb 21, 2016 1:27 pm
Location: Ireland
Contact:

Re: EMO-R8 intermittently not seen by i2c

Postby Merv » Wed Jun 01, 2016 10:54 pm

Hi,

I wrapped the I2C cable in tinfoil, and it worked! That was the problem.

If I am re-wiring the system, I'll re-arrange to keep the cable away from the power supply, but the tinfoil trick is fine for now.

I've been checking it each day for the last 4 or 5 days and it's perfect.

Tomas, Many thanks for the great support work you do here.

Merv.
tomas_hora
Site Admin
Posts: 298
Joined: Wed Oct 29, 2014 9:56 am

Re: EMO-R8 intermittently not seen by i2c

Postby tomas_hora » Wed Jun 08, 2016 7:25 am

I am glad it helped. Thank you Merv :)

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