Howto: PLC Reef Controller II
- Thread starter gabe21804
- Start date
javajaws
Premium Member
Sanjay said:
Its just 3 float switches from floatswitches.net. I have them mounting upside down with a pile of PVC pipe fittings so that they are positioned one above the other. Similar to the second picture on this link: http://www.reeftek.com/reef-relief/index-images.htm.
Everything is still in "test" mode...so I don't yet have the float switch "array" mounted in a container yet...it's just strapped vertically next to my computer and PLC for testing.
slug
New member
If it is the circtuit using the lmc6001 there is some info on the ph circuit on the data sheet: http://www.national.com/ds/LM/LMC6001.pdf
Sanjay
Premium Member
gabe21804 said:
Roy:
I am looking right now for pictures of the wiring inside the enclosures. trying to get a feel for how to lay this all out. there has to be a nice way, right now I have a tangle of wires.
I am going to try mounting all this on din rails, but I cant find the rails anywhere locally... all I get is blank stares. Online sites want me to buy 20 rails at a time.
Also what kind of wires are best suited for this internal wiring of the relays, switches etc. Right now I just grabbed what ever was laying around the house.
As you can tell, my electrical DIY skills are quite lacking.
sanjay.
slug said:
I posted that schematic a page back
, but that is the one I'm using. That datasheet explains it all, just make sure you use a regulated 5vdc ps for it, and a regulated 12vdc power supply. If there cheap wall transformers make sure your meter them. Most of those supplies will flux back and forth by .5 to .25 volts....that can be solved by using a capacitor to smooth out the voltage.But like easttn said, make sure you solder the female bnc end to the pin on the opamp, don't use a wire or pathway to connect it. Also make sure you use a platinum or gold bnc female bnc end.
Sanjay said:Roy:
I am looking right now for pictures of the wiring inside the enclosures. trying to get a feel for how to lay this all out. there has to be a nice way, right now I have a tangle of wires.
I am going to try mounting all this on din rails, but I cant find the rails anywhere locally... all I get is blank stares. Online sites want me to buy 20 rails at a time.
Also what kind of wires are best suited for this internal wiring of the relays, switches etc. Right now I just grabbed what ever was laying around the house.
As you can tell, my electrical DIY skills are quite lacking.
sanjay.
I'll post some pictures later today, try digikey.com. You can buy rails in qty's of 5 I think. There catalog is a 1600 page pdf file you'll have to go through. You also get a good deal on din terminal blocks..etc Only bad thing is they have a $5 handling fee if the order is under $25.
javajaws
Premium Member
Remove the dot at the end... http://www.reeftek.com/reef-relief/index-images.htmSanjay said:
slug
New member
I saw you already posted that schematic but thought the data sheet might be usefull too.
When I got samples of the chips one of them was one of the tiny surface mount types because I didn't specify a package, so if anyone else requests samples make sure and get the right part. I think I'm going to try and solder leads on it but I have to high a wattage and not a fine enough tip soldering iron =(
When I got samples of the chips one of them was one of the tiny surface mount types because I didn't specify a package, so if anyone else requests samples make sure and get the right part. I think I'm going to try and solder leads on it but I have to high a wattage and not a fine enough tip soldering iron =(
slug
New member
I wired up just the left half of the circuit using only the lmc6001 and a couple resistors and this seems to work. I get 295 mV in ph 4 solution and 29 mV in ph 7 solution. A ph 10 solution should give me negative mV but I can't find one.
I think this is good enough to read into a data acquistion device. It makes the circuit super simple and the inversion and zeroing can be done in software.
I think this is good enough to read into a data acquistion device. It makes the circuit super simple and the inversion and zeroing can be done in software.
sailfinreef
New member
I just stumbled in on this thread and it seems very interesting. I have been using allen bradleys plc 3 with a hand controller that i got for free to controll lighting and temp for a while. I really dont have much use for the ph monitor, but if you guys want me to look over some code or have a question I might be able to answer it. I am familiar with quite a few logic Swords.
barebottoms said:
Did anyone take a look at the link? This is straight from the datasheet:
"Use our Electrode Amplifier to collect data with almost any electrode that has a BNC connector. This includes electrodes from Vernier such as our pH electrode (order code 7120B), or third-party electrodes, such as pH, ISE (ion-selective electrode), or ORP (oxidation-reduction potential). The Electrode Amplifier can produce an output in mV, pH (when using a pH electrode), or you can perform your own 2-point, linear calibration."
Just wondering if we can use this for any of our applications since it can accept "an electrode with a standard BNC connector. It amplifies a .390 mV to +400 mV range to the 0-5 V range..."
It would be awesome if it works considering it is only $40
Thanks,
David
slug
New member
It looks like it would work great. It's nice that it amplifies it to a range closer to what most analog in devices read. I'm going to stick with the single lmc6001 because I'd need 3 and I'm cheap and it seems to work pretty well with the equipment I have.
Whether or not you can get an accurate ph from the mv output from one lmc6001 depends on the range and resolution of your analog in.
and it seems to work pretty well with the equipment I have.Whether or not you can get an accurate ph from the mv output from one lmc6001 depends on the range and resolution of your analog in.
slug said:It looks like it would work great. It's nice that it amplifies it to a range closer to what most analog in devices read. I'm going to stick with the single lmc6001 because I'd need 3 and I'm cheap
Whether or not you can get an accurate ph from the mv output from one lmc6001 depends on the range and resolution of your analog in.
Same here I need two ph transmitters, and I'm also cheap. Are you getting the lmc6001 and 6041 as samples from national? I figured it costs about $8 in parts to make these circuits, depending on how my tests go when I get a probe I'll be getting some single layer pcb boards made, maybe a run of 15 or so which would end up being about $3 a board, the circuit would be roughly 3"x3", I dont want to crame it any tighter becaues it has to be hand assembled. It'd be nice if someone could make an arylic case, I tried my handy work with arylic and it didnt turn out too well.
So your looking at roughly $11 in parts with no case for a functional ph transmitter. I'm still in need of platnimum or gold female bnc ends that are made for a pcb board. I only have two gold ones left and I'm having trouble finding that in qty's smaller than 50 cheap.
<b>Slug:</B> What type of plc are you using? I don't remember you talking about it at all?
Similar threads
