Howto: PLC Reef Controller II

gabe21804

New member
Well needless to say the other thread was closed. Rather than try an argue that we were not in the wrong, and there was no illegal activities, ill just start a second thread.

Please in this second thread do not mention the word "SOFTWARE" and refer to all programming and coding as generic ladder logic. Ill give this a second and final shot, if something happens again I'll find a fourm site that will take this project.

For anyone who wishes to catch up in both of the other threads here they are.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=529880

http://www.reefcentral.com/forums/showthread.php?s=&threadid=535018


Respectfully Submitted,
 
Can't wait to get started in developing the code for my own tank. Just waiting on my plc (Siemens) shipment from Easttn. If all goes well I would like to try out one of the ezautomation plc's (as someone else suggested) to compare the two. I'm a college student but it is very beneficial to do some testing for this hobby even if it means spending some hard earned money.
 
eleben said:
Can't wait to get started in developing the code for my own tank. Just waiting on my plc (Siemens) shipment from Easttn. If all goes well I would like to try out one of the ezautomation plc's (as someone else suggested) to compare the two. I'm a college student but it is very beneficial to do some testing for this hobby even if it means spending some hard earned money.

I'd love to see someone purchase a automation direct plc or a ezplc, just to see how it goes. Most of this stuff can be converted between brands with ease.
 
Sure now you tell me. lol. I would have tried the EZplc out. The main concern I have is getting a pH meter interfaced with the PLC. That is what I would like to see happen - I know they use them in industry for water quality tests but I haven't noticed any DIY pH controllers combined with a PLC yet. (If there are any that are setup and have pictures/diagrams I would love to see them) I know you (gabe21804) is working on getting his setup done - but it would be nice to see how everything interfaces together in a "final product"
 
gabe21804 said:
I'd love to see someone purchase a automation direct plc or a ezplc, just to see how it goes. Most of this stuff can be converted between brands with ease.


Glab this topic has been resurrected.

I'll be buying either a EzPLC or a DL06 here in the next couple of days. The only thing I'm hesitant about on the ezplc is that no one else here or elsewhere has much experience with it so I won't have much of a place to go for questions. It'll probably be the DL06 for that reason...

- Jason
 
eleben said:
Sure now you tell me. lol. I would have tried the EZplc out. The main concern I have is getting a pH meter interfaced with the PLC. That is what I would like to see happen - I know they use them in industry for water quality tests but I haven't noticed any DIY pH controllers combined with a PLC yet. (If there are any that are setup and have pictures/diagrams I would love to see them) I know you (gabe21804) is working on getting his setup done - but it would be nice to see how everything interfaces together in a "final product"

Well, on the PLC side of things you need a 4-20 mA analog input. Connected to that is a transmitter which outputs the 4-20mA signal. Connected to the other side of the transmitter is the pH (or ORP) probe. If you would like to know how to take the 4-20 mA signal and turn it into a pH value I'd suggest you look at the AD DL06 manual (or your PLCs manual)...AD has great easy to understand documentation on how this stuff works (specific for the DL06 but the concept is the same for other PLCs). Here's the relevant DL06 documentation...especially check out pages 11 and 12 on scaling raw data values...

http://web2.automationdirect.com/static/manuals/d0optionsm/ch3.pdf

- Jason
 
OK, one more question: How do you calibrate a pH probe...by adjusting the transmitter or something in the PLC?
 
Anyone know of a cheaper source for a pH transmitter. I was just searching for one and there are many available it is just that all of them are easily over $100 just for the transmitter and no probe.

Thanks,
David
 
I think gabe has a schematic for a ph transmitter that he is going to try to build, with anyluck it will work and be a big money saver. If not there are some probes that have a built in transmitter but with probes having to be replaced every so often means your paying extra for the built in transmitter each time.
 
I thought I remembered him talking about the schematic for a pH transmitter. I am definitely on board to get this going. I have an Co-op with Kimberly Clark coming up in June and my tank is at my parents house. I won't be coming home every couple weekends like I do know to take care of my tank so I need to get things running as best as I can so my parents only have to do a little maintenance here and there while I'm gone. pH is a big concern of mine since my tank has such a low pH problem and don't really have any good way of measuring it yet. I bought a Hanna pH meter but I haven't had the best of luck with it. Anyways...I digress back to PLC talk
 
eleben said:
Sure now you tell me. lol. I would have tried the EZplc out. The main concern I have is getting a pH meter interfaced with the PLC. That is what I would like to see happen - I know they use them in industry for water quality tests but I haven't noticed any DIY pH controllers combined with a PLC yet. (If there are any that are setup and have pictures/diagrams I would love to see them) I know you (gabe21804) is working on getting his setup done - but it would be nice to see how everything interfaces together in a "final product"

I just now started to think of the big picture ;) ...We need to be looking at a setup that can be purchased by anyone, and not just someone waiting for parts to appear on a auction site.

Automation Direct Stuff is going to get pricey quick, I think I priced a setup with everything you'd need at $650 with the dl06 as the base.

The ezplc could be the golden ticket, someone just needs to purchase a unit and be the test subject. Or try and write a real good email and get a free sample unit, some companies will send you a sample if you can prove it will benefit them.

As for the ph/orp....etc interfaces I have a schematic of a ph transmitter with a calibration circuit built into, parts are roughly $40-$60 I'm guessing, I'm going to suck up the cost and see if I can't get something working, this may save a ton of us some cash. I can't afford to drop $150 on just the transmitter.

Law: By any chance did you take a look at the code I gave you? If so did you figure out whats wrong with it? Mainly Im trying to use that as a base to datalog from 8 different byte addresses, save the addresses and plot them on a graph. I'd like it to resemble something you see in a control room in a manufacturing plant, that shows the pictures of the pipes on the monitor and which valve is closed...etc but instead of valves the graphs for the probes...

I can figure out the gui part, its just getting that link to the plc that I'm having the problem.
 
Gabe21804 - If you want I would be willing to purchase the EZPLC for testing purposes. I just need to know what I need to purchase - what you think we would need to get this off the ground. Send me the list and I will see what I can do. Also if you want I will send you 1/2 of what it costs to get the parts needed for the pH transmitter.

Thanks,
David
 
I can tell you what you need for the ezplc...but you'll have to make the call on which base PLC unit to get...the one with 4 expansions slots, or 6 (or more). I think 4 may not be enough because you'll have to use 1 for the analog IO and 1 for the thermocouple IO...leaving you with only 2 slots open (8 in and 8 out probably). The 6 expansion unit will probably be better. I'll post later tonight with a shopping list if you're interested.

- Jason
 
Sounds good. Just try to do a basics to get things started but of course leave room for expandability.

Thanks,
David
 
eleben said:
Gabe21804 - If you want I would be willing to purchase the EZPLC for testing purposes. I just need to know what I need to purchase - what you think we would need to get this off the ground. Send me the list and I will see what I can do. Also if you want I will send you 1/2 of what it costs to get the parts needed for the pH transmitter.

Thanks,
David

I'd get the programming cable, the evil S word ;) thats banned from this thread, and the plc, and thats it for now. Don't spend anymore than that intial plc portion til we figure out what this thing is capable of. If it looks like it works I'd then look into getting modules. Let me take a look at the specs of the units and see which one looks like your best bet, the issue that may arise is the lenght of code that can be programmed into the units. I complex setup code have an extremely long code length.

Ill let you know when I attempt this ph transmitter, its on hold for the next week or so, still have no clue whats going on with me.
 
Eleben:

I'd get the EZPLC-A32

If you feel youll go over 32 inputs and outputs I splurge for the EZPLC-A48....that choice is on you. Ethernet looks extremely intresting considering its built right on, I'm not that far in my project yet, so that choice would also have to be on you.

From what I'm seeing the rs232 port can be used as a programming interface and a HMI interface (AKA LCD screen..etc), I'm not sure if its possible to link back to a computer with this port on this particular product this would require more research. Although the ethernet port looks like its a direct link that can be used to monitor it. If you can afford it and your not hurting yourself I'd say go for the ethernet if not we can work around this, an ethernet module for my plc costs entirlely too much new or used for me to look into it at the moment. As I said I'm trying to keep the cost down as much as possible, if we can get this up and running not just on mine but someone with something you can buy easily it may make this project more attractive.

Also for now I'd just get one Digital DC Input and output, this will allow you to use 24VDC relays to trigger your high voltage stuff which will be cheaper than using the ezplc relay module.

Get the programming cable, and the evil S word.

Hold off on the analog i/o module til we get to that step in the project and have the rest of your setup working.

So right now your looking at this.

EZPLC-A32 ($129) or EZPLC-A48($168) or you can opt for the ethernet option thats your decsion.

Digital DC Input Module ($19)

Digital DC Output Module ($19)

Programming Cable ($30)

Evil S Word ($49)

Thats all you'll need to figure this unit out, you can purchase additional modules once you've got the basics running.
 
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