Hi folks this is my first post. I have tried to read as much as I could over the last week or so
I have tried a few searches and cant find the answer to my questions. I have many the learning curve is steep.
I will start with two if I may?
1. I have two efergy clamps they had two different connectors on them I want to replace these connectors with ones that fit the TX shield board I have just assembled. I cant find a "pinout" for the 3.5m jack, is there one like the one for the temp sensor.
2. I think I have got a bit turned around with the effergy vs recommended ct clamp facts. I think I am seeing confusing advice. where at one point someone says the two clamps are very similar, and others are saying there is 1350 or 1410 coils, as I have soldered up the emontx shield with the standard components will this work with the efergy clamps with the correct connectors, or do I need to change out one or more of the resistors on the board.
Re: changing connectors on effergy ct clamps for use with tx shield
1.) You can find the pinout in the http://solderpad.com/openenergymon/emontx/ Pin 2 (the middle connector of the 3,5mm jack) is not connected. So you have connect your sensor to pin 1 & 3.
2.) If the difference betweens the windings of the CT sensors is so small then you can adjust it by modifing the http://openenergymonitor.org/emon/modules/emontx/firmware/calibration
Re: changing connectors on effergy ct clamps for use with tx shield
The Efergy c.t. is not recommended for use with the emonTx. Inside the body, there is a small network comprising diodes and resistors that seriously distorts the output waveform, making it unsuitable for the way the emonTx measures and calculates current (and hence power). This has been discussed, and a solution if you do not wish to discard your Efergy c.t's is here: http://openenergymonitor.org/emon/node/476
We can only speculate the reason for that network. My supposition is that as the Efergy meter neither calculates power nor its direction (it estimates power assuming a constant voltage and power factor), it is part of the input rectifier and signal conditioning and is intended to expand the range at low currents. The emonTx, when used with a voltage monitor, accurately calculates both power and its direction.
Re: changing connectors on effergy ct clamps for use with tx shield
Thanks for that info jb79 I will connect up the jack as you suggest.
Robert, I did see the thread you link to in my research and it is only now after I read it again with your explanation that it makes sense. I can gut the internal components and add the burden resistor at the same time I add the Jacks.
I would like to use these as I hate throwing things away and buying new. Reuse, recycle, upcycle, ( read cheap) ;)
Thank you.
Edit. update: I have soldered up the ct clamp now oddly it had no additional components just a coil on a board.....
weird they are identical apart from the sticker but the one labeled efffergy has the extra electronics.
Re: changing connectors on effergy ct clamps for use with tx shield
Just check that you don't have two burden resistors. There is already a 33 Ohm burden on the emonTx shield pcb.
If your Efergy c.t. is black, (the old version), I measured the turns ratio as 1410, Efergy state 1350. I didn't test it without the conditioning network. I don't have any details for the white (new) one.
Re: changing connectors on effergy ct clamps for use with tx shield
These ones are both grey with white leads
I will check the resistors tomorrow as after wrestling the tx shield Into compliance with the raspberrypi shield I now have data but confusing and incomplete data, and it is late
At Least they are talking, :).