Tektronix tkdpo7k driver: Get number of aquisitions from the oscilloscope

[torbensa]

Hello,

in our lab we use a Tektronix DPO5204b to record a transient signal. Right now we want to automate the measurement process and in order to control the oscilloscope via LabVIEW 2015 I installed the current tkdpo7k driver on the PC (http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=2510E601F77D020AE0440003BA7CCD...). The oscilloscope is connected via and USB cable (male A for PC and male B for oscilloscope) and first tests were successful. We are able to initalize, set up several parameters or trigger events.

For our experiment we setup the average acquistion mode, acquire 50 acquisition and then stop the acqusition. The oscilloscope acquire when it is triggered by an external photodiode (every 6 seconds). Right now we are able to setup the acquisition and to perform an acquisiton every 6 seconds. But I need access to the acquisition "counter" of the oscilloscope, so the program can automatically stop when it reached 50 acquisitons. The problem is that I can not find any VI which gives me an output on the number of acquisitions.

Currently I use a timeout of 50 x 6s to acquire only 50 waveforms. But this method fails if the photodiode misses a signal or the level is to high. Maybe you guys have a better idea for me.

I also have a second question which is kind of similar to my first one. The transient signal recorded by the oscilloscope is produced by a continuous wave laser hitting a light detection device, which "transforms" the optical signal into an electrical signal. I can tune the frequency of this laser and by doing this, the offset on the vertical axes of course changes. Similar to my problem above I would like toget access to the current offset value in the oscilloscope.

To explain the reason behind this I will shortly explain what we want to do. In principle we want to record the transient signals of this laser at different frequencies. But we would like to do this at the same vertical offset value. The desired offset value is set at the beginning and we do the first measurement at the first frequency. Afterwards the frequency is changed, resulting in a changed offset (stronger or weaker light intensities are the reason for this). I need to know this "new" offset value to attunuate the light to get to the same offset as before.

Thank you in advance and best regards!
Torben

[Kyle97330]

A lot of manufacturers, including Tektronix, only include a subset of their available commands in their driver sets that they distribute.  If you download a manual for your device from Tektronix, you might find a command that does the query but that isn't in any of the VIs in the LabVIEW driver set.  

In order to issue that command you'll need to create your own VI.  You can probably find one of the existing VIs that does something very similar (issues one query command that is converted to a number and then output) and create a copy of that as a starting point.

[torbensa]

Hello,

thank you for your answer.
I found a farely easy solution for this problem. So the driver delivers two VIs which allow to read and write to the instrument. Until yesterday evening I did not know that I could write every command given in the programming manual in this write function. In this manual there are functions which do exactly what I want.
Sorry a bit more research and I would not had to bother you!

Best regards!
Torben