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Re: Salinity Probe not recognized

Posted: Sat Jul 06, 2013 6:31 am
by rossbryant1956
RA reports 6 ppt when it cannot see the probe. Mine is disconnected right now during my re-wire and the portal says 6 ppt.

Re: Salinity Probe not recognized

Posted: Sat Jul 06, 2013 7:37 am
by Sacohen
Fine, but my point is that I wasn't doing a re-wire or anything.
There was no reason for the probe to not be seen.

Re: Salinity Probe not recognized

Posted: Sat Jul 06, 2013 8:59 am
by rimai
The minimum value of the salinity module can measure is 6ppt. That's why you get 6 showing up.
Anything lower than that will require a different probe, but we are really not interested in less than 6 ppt anyway.
Not sure what was going on, but this will let the pump go on when it finds 6ppt:

Code: Select all

if (ReefAngel.Params.Salinity<350 && ReefAngel.Params.Salinity>60) ReefAngel.Relay.Off(Port8);

Re: Salinity Probe not recognized

Posted: Sat Jul 06, 2013 10:51 am
by Sacohen
Right now I have the code commented out and I'm going to keep an eye on things for a bit and see if and when it happens.

At first I thought it maybe happening when my de-nitrification unit sumps water back in the sump at 1, 7, 1 and 7, but I don't think so because it happened at 1 and 5:45 and did not happen again at 1pm. There was a slight dip at 1pm of about .2 ppt, but that's nothing.

Re: Salinity Probe not recognized

Posted: Fri Jul 12, 2013 9:31 am
by Sacohen
This issue of dropping to 6ppt or not being recognized has stopped, but now I'm having spikes of 36 ppt a couple of times a day.

It usually reads 34.5-34.7 ppt, but I've noticed jumps up to 36 ppt several times during the day and these are very brief time.

This is from 1:30 am to 7:45 am today.

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Re: Salinity Probe not recognized

Posted: Thu Jan 26, 2017 8:44 pm
by Diverjoe
rimai wrote:The minimum value of the salinity module can measure is 6ppt. That's why you get 6 showing up.
Anything lower than that will require a different probe, but we are really not interested in less than 6 ppt anyway.
Not sure what was going on, but this will let the pump go on when it finds 6ppt:

Code: Select all

if (ReefAngel.Params.Salinity<350 && ReefAngel.Params.Salinity>60) ReefAngel.Relay.Off(Port8);

I had asked earlier about doing EC monitoring for my freshwater tank. You had replied that the Salinity was simply an EC monitor. I looked at the code and the formulas didn't appear too cumbersome to "undo" any Salinity calcs so I got one. It is all hooked up and shows up on the portal. But, the only way i get anything but 6ppt is to dip it into my fertilizer bottle and there I get 52. When i do a straight Salinity.read - which is where it looks like the raw reading from the expansion occurs i get a 60 back on the serial.print stmt in serial monitor - which is based on other similiar readings is to be taken as 6.0 ppt. Ok, so what I am wanting from it is just the raw microSiemens reading from the probe. Do either of the two jumpers on the board alter the output in any way? Where could i get a different probe if that is what is needed.

Re: Salinity Probe not recognized

Posted: Fri Jan 27, 2017 8:00 am
by rimai
just google for the equation to convert ppt to microSiemens.

Re: Salinity Probe not recognized

Posted: Fri Jan 27, 2017 8:14 pm
by Diverjoe
Can you tell me what JP1 and JP2 are for? Right now they are both completely open. 6ppt is not low enough for anything in freshwater. The readings that are important are around 5-200 ppm (~0-400 uS)

Thanks for being patient with me as I muddle through this!

Re: Salinity Probe not recognized

Posted: Fri Jan 27, 2017 10:35 pm
by rimai
They are test points where you can connect an oscilloscope to troubleshoot the circuit.

Re: Salinity Probe not recognized

Posted: Sun Jan 29, 2017 6:36 am
by Diverjoe
Is the expansion hard coded to not return below 6ppt? The probe is a K=1 rated and goes down to 5uS. (7 ppm). That is the middle ranges probe.


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Re: Salinity Probe not recognized

Posted: Sun Jan 29, 2017 11:52 am
by rimai
I haven't tried with K=1.
Do you have one to try?

Re: Salinity Probe not recognized

Posted: Sun Jan 29, 2017 1:52 pm
by Diverjoe
the probe is a k=.99 which is the same. The higher the number the less accurate. K=.1 is good down to .5 uS, 1 down to 5uS and 10 is good for 10uS

Re: Salinity Probe not recognized

Posted: Wed Feb 07, 2018 8:00 am
by dedvalson
From my understanding a probe of K=1 is not really suitable for saltwater readings. I believe that generally probes for saltwater have a K of 2 or greater with 10 being very common.

Am I misunderstanding something here? What is the K of the probe shipped with the RA?

Re: Salinity Probe not recognized

Posted: Wed Feb 07, 2018 8:49 am
by rimai
It uses K=1, but we never saw any problems with reading values.