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PicoLog scaling file

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PicoLog scaling file

Postby Afernandes » Thu Sep 20, 2012 2:20 pm

I need to write a scaling file for my PT100 data logger (Pt-104) .
The type is table and unit is Ohm.
All four channels need to be scaled with different values.
The information contained in PicoLog User's Guide is unsufficient for this purpose.
Help please.
Afernandes
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Re: PicoLog scaling file

Postby Pico Stuart » Fri Sep 21, 2012 4:03 pm

HI There,

Thankyou for post with regard to your scaling requirements using the PT-104 and PicoLog. PicoLog will allow you to scale each channel individually.

To start a new run from scratch, select New settings from the File menu. PicoLog will take you through the steps necessary to define what you want to collect:

1a.png
1a.png (16.44 KiB) Viewed 1992 times




Parameter options

To access this dialog, click the Options... button in the Measurement dialog for the
converter.

1c.png


In parameter options select scaling

1d.png
1d.png (21.13 KiB) Viewed 1992 times


2.png


Scaling Method. There are three scaling methods: None, Table lookup, and
Equation. You can also read in a lookup table or an equation from a file.
Table lookup. This is useful for a set of input readings corresponding to different
values of the measurement to be scaled. You can put two or more pairs of values in
the box below. For example, to convert a 0 to 2.5 V input to –40 to 100 °C, enter
the following details in the box:
0 -40
2.5 100
Two pairs are sufficient if there is a linear relationship between the raw and scaled values. For non-linear relationships, the required number of pairs depends on the maximum acceptable interpolation error. If you wish to enter more than half a dozen pairs of values, it is better to enter the table into a file, and then use file
scaling (see below).

Equation. This can be used when it is possible to calculate the relationship
between the input reading and the measurement value. The raw measurement
values is represented by x. For example, to convert a temperature from Fahrenheit
to Celsius, the equation would be:
(x-32)* 5 / 9

File. When you specify that you wish to use a file for scaling, this button is
enabled. When you click this button, the computer opens up a dialog to select a
scaling file.

You can scale each channel individually.

Hope this helps,

Kindest regards,

Stuart
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Re: PicoLog scaling file

Postby Afernandes » Mon Sep 24, 2012 1:36 pm

Hi Stuart
Thank's for your help. What I realy need is the information that cannot be found in the user´s manual.
For example :
Scaling file extension : *.scl
1 scaling file for each channel (!)
Now I can make proper measurements with PT-104. Before scaling the Resistance measurement error was 60 ppm.
After scaling the measurement error is 6 ppm, maximum.
However, I have to convert resistance measurements to ºC using a spreadsheet and a curve fit.
I will not send back the datalogger for calibration because measurements drift out of specs in about 3 month.
This means 4 calibrations a year !
There's a huge margin for improvement your product.
Afernandes
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Joined: Thu Sep 20, 2012 2:04 pm


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