Dear Martyin,

Thanks for your information. But how you write a .DDS file with linear scaling? I need to see an example for use of
Method 1, Gain and Offset. Is it is possible to enter an equation as well?

Glovisol

Referring to my previous posts, I was unable to use a .DDS file for scaling the Resistance measurement values: it simply did not work. For this research I have been using a table top with WXP/SP3. Eventually the system behavior was so erratic I again started suspecting something was wrong with the s...

Ohmmeter4.xls It is possible to do an even more accurate resistance measurement using the Ext. Input if it is possible to keep the resistance to be measured floating above ground. In this case the negative supply for the Op Amp is no longer necessary, because we make the Op Amp see a positive volta...

XY Graph0-25K.jpg System measuring 10 KOhm.jpg I am enclosing pictorials showing operation of resistance measurement method. These pictorials were obtained by replacing the resistor to be measured witha multi-turn pot. In the next post I will show a much simplified interface (no ext. supplies) to o...

If you use the same values in a lookup table in the Scaling dialog for Input channels, are the readings scaled correctly? To make sure a new .DDS file is picked up, it is advisable to start Picolog afresh, as soon as the new file is placed in the folder. However after many tests it seems to me that...

DrDAQ Buffer data.JPG Ohmmeter3.xls A way to do good precision resistance measurements with the DrDAQ follows The previously described method works very well if an OP AMP buffer is used before the External input. The enclosed example shows the Ohm measurement done with Ext. 1 input. First of all en...

A way to do good precision resistance measurements with the DrDAQ follows As far as I could see it is not possible to write scaling equations in the .DDS file. The proposed mehod can be implemented in theory by building a scaling table in the .DDS file taking the Vclc values from the Ohmeter 2.xls ...

A way to do good precision resistance measurements with the DrDAQ follows. The enclosed EXCEL file shows the result which could be obtained by placing a 100 KOhm resistor between the +5V output (pin 4) and input (pin 1) of an auxiliary input and then the resistor to be measured (or the variable resi...

PLEASE HELP! 1) I need to see the example of a .DDS file for linear scaling (e.g. using Method=1). This is of course possible within the Picolog's menu, but is would be most useful if it could be done by a separate file. 2) I also need to know if it is possible to write an exponential equation of th...

Dear Martyn,

Thank you!! Got it now. Each resistor value identifies the corresponding probe.

I tested the accuracy of the new USB DrDAQ I received last week. The product specification is as follows: RANGE: 0 - 1 MOhm RESOLUTION: 250 Ohm @ 10 KOhm ACCURACY: 5% I tested the unit in the range 1 KOhm to 1 MOhm with 1% resistors, checked with a high precision / high resolution Standard Meter (Mo...

As per my previous update, the .DDS file was now able to control all parameters of the DrDAQ, but the scaling was NOT operating: e.g. reading shown was without scaling. After many tries the .DDS file became bad and with the file in the Pico Full directory the DrDAQ would not start. This I solved by ...

As per my previous update, the .DDS file was now able to control all parameters of the DrDAQ, but the scaling was NOT operating: e.g. reading shown was without scaling. After many tries the .DDS file became bad and with the file in the Pico Full directory the DrDAQ would not start. This I solved by ...

I examined three PICO publications as follws: 1) USB DrDAQ Data Logger - User's Guide. 2) PicoLog Data logging software - User's Guide. 3) PicoLog Self-Help Guide. The most detailed reference to the Auto-Detect resistors can be found in reference 1) above. On page 32 we read: Auto-Detect Auto-detect...

Concerning my previous post on difficulties with .DDS files, I suspected that some other software installed in the PC might prejudice the connection between the .DDS file and the DrDAQ. I therefore took another IBM X61 (W7 O.S.) with a bare minimum of software installed, and prepared the same .DDS f...