# trying to use a pinpoint controller



## carsonc (May 30, 2007)

can any one explain how to set the high and low settings on a pinpoint ctrl
When I move the switch to high and adjust the left screw it will show a value in the readout, but after I move the switch to low and adj the right screw, when I switch back to the high side the value has changed.
I did this back and forth about 10 times but it never would give repeatable readings.
A friend gave me the controller and I downloaded the user manual but no luck yet.
It calibrates ok and gives the same reading as a ph test kit.
I was trying to set it so that the co2 would come on at 7.0 and go off at 6.8
Any help would be appreciated
Carson


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## carsonc (May 30, 2007)

Just as I thought they cannot be made to work  
Carson


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## carsonc (May 30, 2007)

Not too many sugestions out there so I will tell who-ever reads this what I have found so far.
The controller was used on a reef tank before I got it, the person using it thought that it was working when they shut down the tank, the controller was less than a year old. I got a new probe but that did not fix all the problems. I took the cover off the controller and pulled the circuit board out to see if there was anything visible that could cause it to not work.
While looking at the board under a microscope I could see a slight coating on the board that looked like dust but it was stuck to the board and would not blow off. I cleaned the board with electrical contact cleaner several times and was able to remove the deposit (salt creep ???). After putting it all back together it would now calibrate better (still would not go all the way to 4.0 but a lot closer, and the high and low settings were more stable.
It is now working, but the readings that it gives are all off a little 
That's all for now
Carson


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## bhaladog (Jun 8, 2007)

Hi Carson--

If the controller is similar to the Pinpoint controllers I have used previously, the left set screw is the "Range" set and the right set screw is the "Center" set. Adjusting either will change your high and low set values.

I remember the user manual having pretty explicit directions for setting up, but you can either (a) set your range first (using the left screw), then adjust the center value (using the right screw) or (b) vice versa. I think (a) is easier.

The Pinpoints (that I have used) are setup to span between the set high value, and the center value. You should not reach the low value. So, for your example, if you want to span between pH 7.0 and 6.8, you'll want a range of 0.4, and a Center Value of 6.8. Your Low Value is 6.6. It may be easiest to (1) use the Range screw to set the approp range (0.4). You can see the range by flipping back and forth betw the High and Low settings--don't worry now if your High value is off, just get a difference of 0.4 betw the 2 values. Once you have the Range set, switch to High, and adjust the Center Value until you see 7.0. Check the Low Value--it should be 6.6.

Try that out. 

-Mike


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## BryceM (Nov 6, 2005)

If you can't get it to calibrate correctly I certainly wouldn't use it. pH controllers are sort of a luxury item since tanks can be perfectly happy without them. In fact, the VAST majority of nice 'scapes are created using a simple bubble count method of CO2 dosing with occasional pH monitoring.

I use a Pinpoint controller on my 180g tank, but I'm sort of paranoid about calibrating and replacing probes frequently. Like bhaladog said, there are four set-screws on the front of the unit. Two are used to calibrate the probe. One screw sets the neutral point (pH 7.00) and the other sets the slope (either set at pH 4.00 or 10.00 - most planted tank people use 4.00, since that's the direction we're usually headed).

Once the probe is calibrated you adjust the "control points" with the other two screws. One sets the midpoint and the other sets the range. My particular controller has a minimum range of 0.20 pH units. Currently mine is set to 5.95-6.15. In actual practice pH is controlled between 6.05 and 6.15. When pH goes up to 6.15 it turns on and it turns off again when pH is at 6.05. If the pH ever got down to 5.95 it would activate a second circuit which you could use for an airstone, alarm, or something else.

If you adjust the midpoint, it will affect _both_ the high and low settings. If you adjust the range, it will also affect _both_ the high & low settings. Adjusting the midpoint will move _both_ of the values either up or down. Adjusting the range will move _both_ values either closer or farther away from the center value.

HTH.


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## carsonc (May 30, 2007)

guaiac_boy and bhaladog thanks for taking the time to post. You both mention a range as in .2 or .4 . On the unit I have the range screw gives a reading of 5.2 to 8.3 as if they were ph readings, it has never (since I have had it) had a display of 0.anything. I have tried using the high and low setting on both screws but never seen a display like you are talking about.
The controller was given to me and I thought I would invest the price of a probe to see if I could get it to work. I have the co2 set so that it can't get too out of control. 
It will calibrate to 7.0 ok but I can only get to 4.5 on the 4.0 fluid, there also seems to be a lot of interaction between the calibration points, I have to set each one about 5 times to get it to read 7.0 and 4.5 going back and forth between the 2 calibration fluids.
I have had planted tanks before (before the reef tank bug bit me) and just used a ph monitor, I will probably do that again.
Thanks for you help
Carson


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## bhaladog (Jun 8, 2007)

Hi Carson--

The display will show you (1) the current pH ("Read"), (2) the High Set Point ("High") or (3) the Low Set Point ("Low"), depending on the switch setting. It will not indicate (directly) a Range or Center Point--you have to do the math.

You can compute your Range by subtracting the Low Set Point from the High Set Point. You can compute your Center Point by subtracting half the Range from the High Set Point. 

Try this:

Without turning any screws, compute your Range and Center Value as above. Now try adjusting the Range screw, with the indicator switch on the "High" setting. Turn the screw and you should be able to make the High come down. Now flip the switch to "Low". It should have come up--you've reduced the Range, but if you do the math, you should still have the same Center Value. 

Now play with only the Center Point screw. You should be able to move the High and Low settings by turning this screw, but again, if you do the math, the Range (diff betw the High and Low) should stay constant.

Once you understand how the set screws work, then you can use them to set your values.

-Mike


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## BryceM (Nov 6, 2005)

Yep, what bhaladog said. Wwithout having the manual for the controller it's a bit hard to explain. Have you looked for an on-line version of the manual?


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## carsonc (May 30, 2007)

Thnks again I will try what you said.
I thought I had tried that but sometimes what I thought I did and what I actually did do are two different things.

I did download the manual but it did not help much, other that the calibration 
Carson


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## net (Mar 27, 2007)

Have you called the manufacture? most of the larger company's have a technical help line. Look them up online and go to "contact us" make the call and ask for technical assistance. I am sure they can help.


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## carsonc (May 30, 2007)

Well I did what you said and it worked.    
For a while I will run the co2 at a rate that would not cause a problem if it were to stay on too long. If all works as it should I might bump it up a little.
I do appreciate all your help
Carson


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## bhaladog (Jun 8, 2007)

Carson--

Great! :tea: I remember the manual being somewhat hard to read when I first set one up.


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## mhoy (Jun 12, 2007)

Without a high enough rate of CO2, you might never see if the controller is working, it may always be on...


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