Apex to repair or to replace

[Origami]

They must be exhausting old stock. If you want to send your pictures to Curt, and to tell him your preference for one of the new boards (that he said existed), do so. I'd be interested in hearing how they respond. Since I just sent him an email on Friday, he will not have forgotten the subject.

[Valencia]

does anybody could help me to identify these components?

 

[Origami]

does anybody could help me to identify these components?

 

Not enough resolution on your photograph. Please tell us what's written on top of the chips. I'm suspecting that they be amplifiers / interface chips for the BNC connections but the printing on the top of the chip will help us. Is this your board or something that you pulled from the web?

[YHSublime]

Woah, this is a blast from the past!

[Origami]

Woah, this is a blast from the past!

He probably should have started his own thread...

[Valencia]

I found the photo on the web, and i want to know the part number, because I already have a project and i want to expand it, I am using regular amplifiers, but I was reading that Neptune System is using components more accurate, I have the pH and ORP modules, but I am developing Calcium and Nitrates DIY modules, and I want to use the same precision components. I will post circuits and diagrams to share the project.   

[Origami]

I found the photo on the web, and i want to know the part number, because I already have a project and i want to expand it, I am using regular amplifiers, but I was reading that Neptune System is using components more accurate, I have the pH and ORP modules, but I am developing Calcium and Nitrates DIY modules, and I want to use the same precision components. I will post circuits and diagrams to share the project.

Precision components? If they are amplifiers, they're most likely instrumentation amps with low noise and high CMMR. The layout around the parts will be critical and will probably include guard rings and such to keep noise down at the input to preserve the SNR of the probe input. Look up some app notes for medical instrument instrumentation amplifiers, probe amplifiers, and such. Years ago (before the Internet) I read an article written by Bob Pease on his early years designing these things. It had good, practical advice on the topic that could be useful if you can find it. It was printed in Electronic Design magazine as I recall.

 

The picture there is the inside of an AC3 control module, I believe. I don't have one now. If somebody here does have one lying about, they might be able to open it up and read off what devices were used. Keep in mind that newer alternative parts will exist, and layout of the circuit can be a real performance limiter if not done well.

 

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[Valencia]

The reason its because Neptume system is using Galvanic Isolation componets instead of regular amplifiers, I am using TL084D in pH and ORP modules.

 

 

This is a topic other controller companies like to avoid. Why? Because not all monitoring ports are created equal. Galvanic Isolation is key to getting accurate readings on pH, Temp, ORP, and Conductivity. Some controllers either do not do it well (they are still figuring it out) or possibly not at all.

So what is Galvanic isolation? Well, the tech-answer is that it’s where two or more electric circuits must communicate, but their grounds may be at different potentials. It is an effective method of breaking ground loops by preventing unwanted current from flowing between two units sharing a ground conductor.

Now of course that is all geek-speak to most of us so let’s just put it this way: on a controller without galvanic isolation, your readings of pH, Temperature, ReDox (ORP), Conductivity/Salinity, etc. will be completely inaccurate.  Of course it costs us more to add this circuitry into the Apex, but what good is a controller if it doesn’t give you accurate readings?

[Origami]

So check out some isolation amps from Analog Devices.

 

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