Howto: PLC Reef Controller II
- Thread starter gabe21804
- Start date
Konadog said:
Thats exactally what I was going to post, been out of the loop for the last week.
Rumor has it, that is what seio's controller is going to do when they release it. Hopefully they can do it cheaper than what an actual VFD would cost to do it. Its just not economical to run a VFD on a powerhead, by the time you add the vfd and the ph into the cost, you'll have a tunze + controller if not more spent.
sailfinreef
New member
a vfd increases or decreases the frequency to an ac motor, most of them will change both frequency and voltage to achieve a desired speed
aka_BigRed
New member
OK, here's a question for you guys:
My voltage sensor has a range of +1.5 to +10v and of course pH probe is centered at pH 7 = 0v. I was intending to use a MAX406 op-amp to invrease to a readable resolution, but can I shift the voltage up to the range readable by my sensor? I'd like to upshift voltage so that pH 0 is now +5.75v and ph < 7 gives voltages less than +5.75 instead of negative voltage as normally it would. Is that possible?
I'm not well versed in electronics & IC components, so I have no idea how to proceed. If anyone can help I could really use it.
I've got all my back work documented here with more info.
http://bytality.com/wrrc/index.cfm?task=display&doc=pH_Sensors
My voltage sensor has a range of +1.5 to +10v and of course pH probe is centered at pH 7 = 0v. I was intending to use a MAX406 op-amp to invrease to a readable resolution, but can I shift the voltage up to the range readable by my sensor? I'd like to upshift voltage so that pH 0 is now +5.75v and ph < 7 gives voltages less than +5.75 instead of negative voltage as normally it would. Is that possible?
I'm not well versed in electronics & IC components, so I have no idea how to proceed. If anyone can help I could really use it.
I've got all my back work documented here with more info.
http://bytality.com/wrrc/index.cfm?task=display&doc=pH_Sensors
sailfinreef
New member
you should be able to, you will have to alter your program for that, should be able to change the values in the program. what plc are you using, i might be able to smash something together for an example. do you have a touch pad or something that you are using to view the ph reading.
aka_BigRed
New member
sailfinreef said:
I'm actaully using a Dallas-Maxi 1-wire sensor (DS2438) with a WRT54g router running linx reading it. It's supposed to be used as a battery pack monitor so it's not designed to read neg voltage. I can easily correct for any voltage offset in my software, but I just need a magic circuit that shifts the mV's up so that 0mv is now about 383mbV. Will it work properly when the probe gives negative voltage? (ie neg probe voltage subtracts from 383mv and pos probe voltage adds to it)
Osler@thesea
New member
You will need a Gain opamp followed by a Summing opamp. Somthing like this:
This circuit isn't perfect and I have not constructed it. However, it gives you the general idea. There are others in this forum who could fine-tune this circuit to do what you want to do.
I opted to use the Electrode Amplifier available from vernier (www.vernier.com) as it does exactly the same thing, shifting the voltage to the 0V to +5V range (Gain = 2.2V, Offset/Sum = 1.20V). Output is +0.408V to +1.992V (pH 0-14). This still presents a problem as your input is only +1V to +10V and a +1V ouput from the amplifier equates to a pH of 8.49. Therefore, you'll need an Offset/Sum of more like 2.0V.
HTH.
This circuit isn't perfect and I have not constructed it. However, it gives you the general idea. There are others in this forum who could fine-tune this circuit to do what you want to do.
I opted to use the Electrode Amplifier available from vernier (www.vernier.com) as it does exactly the same thing, shifting the voltage to the 0V to +5V range (Gain = 2.2V, Offset/Sum = 1.20V). Output is +0.408V to +1.992V (pH 0-14). This still presents a problem as your input is only +1V to +10V and a +1V ouput from the amplifier equates to a pH of 8.49. Therefore, you'll need an Offset/Sum of more like 2.0V.
HTH.
sailfinreef
New member
I kinda misread your original question there but it looks like you got a real good answer, that is a good drawing.
Osler@thesea
New member
javajaws:
Here is the link to the pinout for the vernier stuff. Most probes can be ordered as DIN, but some only come in BTA.
http://www.vernier.com/probes/specs/pinout.html
They don't have wire colors, but I have taken one of their BTA connectors apart and the following applys:
Pin 1 (+/-10V input): yellow
Pin 2 (GND): black * (goes to DIN pin 5)
Pin 3 (Vres): green
Pin 4 (AutoID): brown
Pin 5 (+5V): orange* (goes to DIN pin 4)
Pin 6 (0-5V input): red* (goes to DIN pin 1)
* = these are the only ones you care about.
Here is the link to the pinout for the vernier stuff. Most probes can be ordered as DIN, but some only come in BTA.
http://www.vernier.com/probes/specs/pinout.html
They don't have wire colors, but I have taken one of their BTA connectors apart and the following applys:
Pin 1 (+/-10V input): yellow
Pin 2 (GND): black * (goes to DIN pin 5)
Pin 3 (Vres): green
Pin 4 (AutoID): brown
Pin 5 (+5V): orange* (goes to DIN pin 4)
Pin 6 (0-5V input): red* (goes to DIN pin 1)
* = these are the only ones you care about.
aka_BigRed
New member
I've been out of it for a while, but had a couple Q's about the above schematic.
Can I substitute a MAX406 op-amp for both the above LM**** ops he used? I've got a couple lying around, plus Maxim will send you free samples so I'd like to prototype with Maxim parts if at all possible. That way if I toast a couple accidentally, I'm not really out much, and the 1-wire sensors the controller is based on is made by Maxim (Dallas Semi actually)
ronc98, can you post any differences between your circuit and this one? A schematic might be good for the general common knowledge.
Can I substitute a MAX406 op-amp for both the above LM**** ops he used? I've got a couple lying around, plus Maxim will send you free samples so I'd like to prototype with Maxim parts if at all possible. That way if I toast a couple accidentally, I'm not really out much, and the 1-wire sensors the controller is based on is made by Maxim (Dallas Semi actually)
ronc98, can you post any differences between your circuit and this one? A schematic might be good for the general common knowledge.
inerratum said:
My project has been also been sidelined til the end of june. Dealing with a state contract that has penalities involved, and most of my time has been devoted to this.
Ive got my tank up and running, the plc is doing basic functions timing, pumps, on and off cycles, temp cut offs...etc nothing advanced will be added til late june.
Ok so I am being a bit lazy and am not reading through everything......this may have been mentioned already but there are soe really cool smart relays at www.klocknermoeller.com
i had to mess around with one of their EZ relays for a customer of mine and found that they were quite a nice little unit to work with.
I program PLC's for a living and have wanted to set something up on my tank to do automation for a long time but just haven't had the time or the $$ hats off to all of you guys who have taken the plunge!!
just a FYI for all you automation geeks
i had to mess around with one of their EZ relays for a customer of mine and found that they were quite a nice little unit to work with.
I program PLC's for a living and have wanted to set something up on my tank to do automation for a long time but just haven't had the time or the $$ hats off to all of you guys who have taken the plunge!!
just a FYI for all you automation geeks
ribs
New member
I'm going to start writing PLC code for my tank. I have accumulated the following hardware: AB SLC5/03, multiple I/O (contact and triacs), 4-20mA in, 0-10v out, panelview 550 (monochrome touch/keypad). I think I have the hardware down, hehe. Just have to get going on the code, then hook all my tank equipment up.
Those of you who have some logic built already, could you forward it along so I can get some tips on the features and functionality?
Code could be AB (preferably, even up to clogix is ok), but I can handle modicon, ge-fanuc, automationdirect, keyence, etc. I have most software packages, so I could probably read anything ya got, don't do seimens (but a "print to pdf" of the seimens would be ok)
Thanks!
When I come up with some logic I'll post it up for your critique
Those of you who have some logic built already, could you forward it along so I can get some tips on the features and functionality?
Code could be AB (preferably, even up to clogix is ok), but I can handle modicon, ge-fanuc, automationdirect, keyence, etc. I have most software packages, so I could probably read anything ya got, don't do seimens (but a "print to pdf" of the seimens would be ok)
Thanks!
When I come up with some logic I'll post it up for your critique
RV8tor
New member
Hi
I have been taggn along for the last few months and I have been inspired to try this. I have just gotten the
Siemens Simatic S7-226 - P/N6ES7 216-2BD21-0XB0 - 85-264 VAC Supply - DI-24xDC24V - DI-16xRelay (2A). I also have a PPI cable. I will probably need help with the programming, just a basic one for now to do the normal stuff and then, maybe I can add on later.
First question is what else do I need as far as hardware? I would like to control: lights, moonlights, heaters, two external pumps, ph, orp. for now. I do have an electronic backgound but its been awhile.
Thanks in advance for the help and also thanks for all the info you have already posted.
.
I have been taggn along for the last few months and I have been inspired to try this. I have just gotten the
Siemens Simatic S7-226 - P/N6ES7 216-2BD21-0XB0 - 85-264 VAC Supply - DI-24xDC24V - DI-16xRelay (2A). I also have a PPI cable. I will probably need help with the programming, just a basic one for now to do the normal stuff and then, maybe I can add on later.
First question is what else do I need as far as hardware? I would like to control: lights, moonlights, heaters, two external pumps, ph, orp. for now. I do have an electronic backgound but its been awhile.
Thanks in advance for the help and also thanks for all the info you have already posted.
.
sailfinreef
New member
a thermalcouple mod. or a 4-20 input card with a transmitter for your temp and ph etc. some cube relays so you dont trash the relay cards. Im pretty fluent with the allen bradley plc 3 and5's so if you have any questions with some of the programing I could probably help you out.(if your not sure what chips do what or even ladder logic) I could write it up for you in trilogic which is basicly the same as ab code.
Similar threads
