I have just received a brand new USB DrDAQ and I have been unsuccessfully trying to make it work reliably on EXT. INPUTS 1 - 2 & 3 with scaling .DDS files.
1 EQUIPMENT IS AS FOLLOWS.
PC: IBM ThinkPad XS61
OP. SYSTEM:Windows 7 Professional.
2. EXT. SENSOR
LM 35 Temperature sensor fed by the DRDAQ 5 V output of each EXT. INPUT.
Autodetect resistor between pins 2-3, EXT. INPUT: 3.3 kOhm.
With local temperature of 20.5 °C each input (without scaling) reads correctly 205 mV. Standard Pico temperature probe connected to EXT. INPUT 3 reads 20.5°C and internal scaling file for standard probe works correctly.
3. MY SCALING FILE: Experimental.dds
The scaling file was written on Word Pad as a .txt file, then copied into C:\Program Files\Pico Technology\Pico Full and then changed from Experimental.txt into Experimental.dds.
I then connected the LM35 3 wires to EXT. INPUT 1 with a 10 KOhm ballast resistor between Pins 1-2, the autodetect resistor of 3.3 kOhm between pins 2-3 and the supply input of the LM35 to Pin 4.
With the DrDAQ connected via the USB port, I opened Picolog, went thru the standard steps, activated EXT.INPUT 1, went to "OPTIONS" and selected "scaling by file". The system does not see .DDS files directly, unless you click on "all files". The Experimental.DDS appeared in the PicoLog window, but sometimes it had no effect whatsoever; sometimes it just did the correct scaling, but did not change the titles and units. Just once I had the proper performance, but, when I tried to reproduce it a second time, it failed.
Subsequent tries on the other EXT.INPUTS gave similar results.
I tried to re-start the PC; to disconnect and re-connect the DrDAQ. I removed PicoLog along with the entire directory; I re-installed PicoLog again (always used Ver. R5.23) but the action of the .DDS file on the PicoLog/USB DrdAQ combination remains impredictable and unreliable.
The last straw is that sometimes EXT. INPUT 1 appears TWICE on the channel list on PicoLog and sometimes some of the titles and scaling of the Experimental.DDS file appears EVEN IF I HAD THE FILE REMOVED FROM THE Pico Full directory!!
It looks like a mess to me: any suggestions? Where did I go wrong?