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Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 5:11 pm
by carlii
Well I had the ph expansion sorta working for a while. The calibration numbers were way high though. 1239 for 7.0 and 1600+ for 10.0. Then suddenly while calibrateing the 10, the number dropped to zero. After a power cycle, the LCD would blink three times and then go blank. If I unplug the ph expansion, everything runs fine. When I plug it back into the expansion hub, the same thing. Help!

The unit seems to be functioning ok with the LCD screen blank.

Re: Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 7:29 pm
by carlii
I fixed the blinking issue. I had a loose USB connection.

However there is a problem. The ph expansion probe isn't registering properly. When I go from the 7.0 to 10.0 solution, the ph value doesn't change much.

The calibration doesn't settle either.

Re: Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 7:58 pm
by rimai
You mentioned it was giving you 1200s and 1600s, which sound about all right.

Re: Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 8:59 pm
by carlii
I get a low of 1151 and a high of 1588. The problem is that the ph reading doesn't change. Additionally, these numbers give a ph of 393. This can't be right. I've dipped the probe in multple solutions to no avail. The problem occurs with either probe in the expansion unit. Both probes work fine when attached to the head unit.

Re: Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 9:24 pm
by rimai
What is the number you get by entering on calibration mode, but with the probe in tank water?
Don't hit OK though, cancel it or it will overwrite the calibration you just did.

Re: Trouble with ph expansion unit.

Posted: Tue Jul 03, 2012 9:35 pm
by rimai
I think I found the bug.
Open ReefAngel.cpp and go to line 766

Replace this:

Code: Select all

		Params.PHExp=map(Params.PH, PHExpMin, PHExpMax, 700, 1000); // apply the calibration to the sensor reading
With this:

Code: Select all

		Params.PHExp=map(Params.PHExp, PHExpMin, PHExpMax, 700, 1000); // apply the calibration to the sensor reading
Does it solve the problem?

Re: Trouble with ph expansion unit.

Posted: Wed Jul 04, 2012 6:54 am
by carlii
You Da Man!

There is a second edit necessary. It requires the same change on line 701.

It works now!

Re: Trouble with ph expansion unit.

Posted: Wed Jul 04, 2012 8:32 am
by rimai
Thanks for reporting back.
I'll make sure to fix the bug on the next release :)