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DrDAQ pH not displaying appropriately

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DrDAQ pH not displaying appropriately

Postby Guest » Thu Oct 29, 2009 10:50 pm

I have a pH probe with the DrDAQ kit and when connected to the Pico card, it doesn't seem to read appropriately. When I received it in the mail, the bottle solution had dried out. I re-wetted it and then I attached it to a free-standing pH meter it works perfectly fine, calibrated appropriately for 10, 7 and 4 range as normal.

I had intended to leave the probe and log change in pH of my NaOH solution over time, but after a 3hr run, I found that the pH had not changed significantly when it should have with what I was doing to the solution.

The reading for supposedly pH13 NaOH turns out to be only reading 6.5, and when put into pH10,7,4 solutions when attached to the DrDAQ card, it sits between 6.5-7.

Is this a software issue? Since the probe appeared to operate fine when attached to another measurement device.
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Re: DrDAQ pH not displaying appropriately

Postby don.chiou » Thu Oct 29, 2009 10:51 pm

The above post was mine, but I seemed to not have been logged in.

Regards,
Don Chiou
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Re: DrDAQ pH not displaying appropriately

Postby ziko » Mon Nov 02, 2009 1:32 pm

Hi,

Are you using PicoLog Recorder or PicoScope 5? Also what version of the software are you using?

Are you taking into account temperature compensation when immersing the probe in the liquids? You may need the external sensor:

http://www.drdaq.com/sensors.html

However the readings do look quite off, let me know how you get on.

Kind regards
Ziko

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Re: DrDAQ pH not displaying appropriately

Postby don.chiou » Tue Nov 03, 2009 12:02 am

Using the picolog recorder, not picoscope. The version is 3.2(I think? the one on the disc supplied with it). An external probe? I have the normal probe as seen on that link you put in your post. The temperature compensation is not relevant since testing of the probe with the same solution on a non-logging meter reads appropriately.
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Re: DrDAQ pH not displaying appropriately

Postby ziko » Thu Nov 05, 2009 10:11 am

I don't know what that software version is, you can find out by clicking on help then about.

It also seems to me that your probe has dried up and may not be measuring accurately. Please email us at support@picotech.com for further assistance.

Kind regards
Ziko

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