Salinity Drift and why?

[iamchadster]

PPT.JPG

So over the past week, maybe a bit longer I have started to notice a pattern in my PPT reading. Standard for me is right around 34, but I started getting some alerts that I was drifting above 34.5 and I am trying to figure out what the heck is going on. Tonight I started digging a bit into what else happens during those drift times and they match up perfectly with the start of my Radion programming. The Eb8 amp reading that I have overlapped with the PPT reading seems to not only match the drift in PPT well, but it matches the time my Radions turn on (about 7 a.m and 5 p.m) and off. I looked at other things such as evap and when ATO happens, temperature, etc...and nothing really matches up with that pattern in my PPT drift as well as the change in amperage. I think I am going to leave the Radions off tomorrow and see what happens.

[aquamanic]

The conductivity probes are pretty responsive - if you move it to a cup of tank water while the lights are on, does the value immediately drop?

[iamchadster]

I will try that when I get home, maybe ramp up the lights to full intensity at 12k to mimic the midday config. and see what happens.

[iamchadster]

I cranked the lights on and sure enough the amps went up and the ppt started coming down. in fact when I turned the lights off it showed a spike of drop in power on the eb8 and oddly enough the ppt shot up to 35.1. I am going to try this again with the probe out of the tank and in a cup of tank water. if the cables from the radions and the probe cable are zip tied together or run together for any length in the stand could the electromagnetic field given off affect the salinity probe. I have them running very close together.

[zombie]

Thats a possibility. I dont think either cable is shielded.

You might be an engineer if...You have no life and can PROVE it mathematically.

[iamchadster]

the spikes shown in the graph are amazing to me to see. I am not that worried about the tank health of course because I know the ppt isn't shooting up and down like that. But the radion cable doesn't touch the water to create any loose voltage. if I take the probe out of the tank and get a similar result then I guess I can try separating the cable a bit and see if that changes anything. Wouldn't the cables coming from the radions transformers to the radions be the issue? maybe the probe line is in too close of proximity to the actual transformer. I dunno it's just really bizarre.

[iamchadster]

Here is when I turned the lights on then Off.
PPT spike.JPG
The Orange is the amp draw due to the radion coming on, the grey is the ppt shooting up right after the lights turned down. I am going to repeat the test with the probe out of the tank now and post what happens.

Capture.JPG

[iamchadster]

datalog.JPG

Ok, with the probe out of the tank I was able to replicate the identical behavior. The probe is sitting in a paper cup with about 1 cup of water in it. Something else has to be going on. I also took a look at the cable routing I have and really the cables from the transformers to the radions are not near the probe cable.

powerppt.JPG
In a matter of 15 min or less the tank took a full 1 ppt drop when the amperage changed on the Eb8's. Should I plug the PM2 into a different aquabus port? Any other ideas?

[BertL]

Chad, FWIW, I had similar odd things go on with my salinity probe and "drifting" as you call it, that I never figured out despite using many packets of calibration fluid, and I couldn't tell you have many different combinations of things I tried isolating the issue. Like you, I also found the reported salinity would begin to change when the probe was in a separate container, in my sump, or in my tank -- with and without the temp probe also attached to the PM2. To your question, I found no difference plugging the PM2 into different places on the aquabus, using either of it's aquabus ports, or a different "USB" cable. My pre-setup query didn't come up with any reported issues or gotchas, but to this day, I suspect interference of some sort was the cause of my PM2/salinity probe problems. I'll never know, as I ended-up removing this point of frustration from my setup weeks ago. ;-) Continued good luck in your pursuit!

[aquamanic]

Can you plug your Radions into a wall outlet instead of the EB8 and repeat the test? Run an extension cord if you have to but try not to change the location of the wires if possible - just one variable at a time.

That should isolate the high voltage (110v) completely from the controller and Aquabus.

See if your conductivity probe responds the same way when you apply power to the fixtures.

[iamchadster]

thanks bertl, and yes Al I will go change it right now.

[BertL]

Al -- that's one I didn't try. FWIW, my two Radions were plugged into an EB4, but it and all Radion wiring were completely isolated (behind my tank and on opposite end) from where the PM2 and my probes were (in the sump area on the other end of the tank).

[iamchadster]

just playing with my phone I was turning the radions off and on separately and watching the ppt. each radion is plugged into a separate eb8. I would turn one off and the ppt shot from 33.9 to 34.4. my expected value is 34.3. Now I know it's just not one eb8 Outlet or one radion doing it. somehow as bert and I have discovered the radions appear to create an interference and a resultant drop in ppt. Al, I have yet to unplug from the eb8 yet but I will do that in a few here and will post the results. I don't ever recall seeing this behavior. Btw I can crank the amps up on the eb8s with heaters and other equipment and it doesn't affect ppt at all. only the radions and as I have posted in a manner that appears to be related to intensity. if running the radions on an outlet other than an eb8 is necessary I can but I hate having the radion fans run when the lights aren't on.

[BertL]

Chad, appreciate as always your update. I find this latest experiment VERY INTERESTING...

[zombie]

If the test with the Radions in a nearby wall outlet gives you the same result, also try a wall outlet that uses a different breaker. I have ran into this issue on a few petrochemical plants and that is the simplest fix in most cases. My guess is that the radions use a half wave rectifier in their power supply which injects a DC voltage drop that can change the reference voltage used by the PM1 to get the salinity reading. By moving the radions to a different circuit, the resistance of the wiring of your house will filter out this interference so the cond reading stays consistent.

You might be an engineer if...You have no life and can PROVE it mathematically.

[BertL]

FWIW, in my setup, there are a couple variables Chad may not have:

- I have two separate circuits running my tank with EBs split across them. Both Radions are on the same circuit, since nothing bad will happen if they are both out for some reasonable amount of time. Since the PM1 draws power from the Aquabus, I'm not quite sure which circuit it gets it's power from in my setup, especially as I also have a 12V power supply powering my controller as well. :-)

- There are at least two versions of power supplies with Radions. I do not have the standard ones that most people probably have when they buy them new, as one of mine kept blowing all GFCI outlets in my home except for one very old one interestingly enough. They of course worked fine in a non-GFCI protected outlets, but that was not acceptable to me for the long haul. I called EcoTech who said that some number of customers had the same problem, so they sent me "non switching" power supplies as replacements earlier this year under warranty, and that's what I have and used with my PM1/Salinity Probe exploration project. ;-)

[aquamanic]

if running the radions on an outlet other than an eb8 is necessary I can but I hate having the radion fans run when the lights aren't on.

Let's first see if that's even the solution. If it is, I have an idea on how you might be able to get around it.

[iamchadster]

OK I will test right after the kids baseball.....

[iamchadster]

Just plugged both radions into a different circut and let's see what happens......................Guess what. Appears to be no drift in PPT if I am not plugged into the EB8? So now what and why would this just start? I have owned the Radions for over a year and have had this config. My PPT is locked on 34.6 and this is what I would expect.

[aquamanic]

So now what

First, I'd test it a bit longer and observe the readings. Did you try different outlets in the EB8 by any chance?

You might just have a faulty EB8. Do you only have this one EB8?

[iamchadster]

Yeah that's the thing. FYI still holding steady at 34.6. I can turn the lights on and replicate this immediately. Lights on and within 10 sec, the PPT drops. So the fact I have the lights on now and no drop in PPT tells me that was the problem. No I haven't tried different outlets, but I have 2 eb8s. I have each radion plugged into each one just for load sharing purposes. So independently I was able to replicate this phenomenon on each radion on different eb8's. If I plug either Radion back into the Eb8 I start to get the drop in PPT again. So a draw on the high volt side seems to be messing with that reading. As I said, I really don't want those fan on 24/7. Wish the fans were programmable like the lights via the WXM. Is there any way to somehow eliminate that interference with some kind of a plug or something and still be able to plug into an eb8?

[Alain B]

I have my 3 radions plugged on the same eb8 and i had never notice any interference with my conductivity reading , i power them off every night . i am following your thread since you had open it and i have paid particular attention to this since you had mention it . I did not notice anything regarding this .

Alain


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[aquamanic]

Chad - I think I'd start with opening a ticket with support. See what they say now that you've narrowed it down and can reproduce the problem at will.

[iamchadster]

Ok, I am going to open a ticket. For the electrical people out there, based on what Zombie said in a prev. post which was way over my head, could having the transformers on the two diff eb8's be a problem? Maybe I should try to plug into the same one and see what happens.

[iamchadster]

Attachment 2974
Never mind, look what happened right when I plugged them in. Yes the PPT dropped right to 33.8, then went to 34. The point is that there certainly is something going on.