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DrDAQ indicate wrong pH

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DrDAQ indicate wrong pH

Postby kiyoshi_abe » Wed Sep 17, 2008 2:04 pm

Hello,
I use DrDAQ for pH measurements and the readings are not correct with the picolog recorder, where the reading is stuck in a value around 7 in all cases. Moreover, readings shows 7.56 in 0.1mol/L HCl solution, and 6.74 is shown in 0.1mol/L NaOH solution.

This situation is quite the same also in Parallel Port and USB Parallel Port
Adapter.

I use picolog recorder rerease R5.20.1 and Windows Vista Home Premium SP1.

Could you please offer a solution?

Thank you
kiyoshi_abe
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Postby picojohn » Thu Sep 18, 2008 3:10 pm

Hello kiyoshi_abe,

It is possible that your pH probe is defective as they can dry out over time and, the easiest check would be to use a known working probe in a buffer solution of known pH.

Regards
John
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DrDAQ indicate wrong pH

Postby Guest » Fri Sep 19, 2008 10:59 am

Thank you.
Each solutions of 0.1mol/L HCl(Factor 0.999) and 0.1mol/L NaOH(Factor 1.002) are both volumetric analysis solution. I am using these solutions for the neutralizing titration.When I measured them by other pH meter, they indicate 1.01 and 13.01 respectively.
DrDAQ displays a wrong pH though the pH probe of this pH meter is substituted for DrDAQ's one.
It seems that this pH probe is not out of order.

When I use picolog recorder release R5.08.6 and Windows Vista Home Premium SP1, DrDAQ indicate 1.10 in 0.1mol/L HCl solution and 12.30 in 0.1mol/L NaOH solution.
However, picopp.sys and DRDAQ32.DLL were substituted as follows.

picopp.sys 2002/07/31 => 2007/07/02 (R5.20.1)
DRDAQ32.DLL 2002/07/31 => 2008/05/02 (R5.20.1)

Best Regards.
Guest
 

Postby ziko » Mon Oct 27, 2008 11:33 am

Hi sorry for the delayed response, John does not work with us anymore.

There may be a problem your DrDaq. Please email us at support@picotech.com so we can look into this further.

Kind regards.
Ziko

Technical Specialist
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Postby ziko » Mon Oct 27, 2008 11:44 am

Actually one other thing you can try before sending us an email is to short out the BNC connector using a terminator plug (or paper clip). The reading on the screen should be pH 7 (0.5).

Kind regards
Ziko

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