Vertical range of the oscillosco​pe during the measuremen​t

Question

Hi all,
I am using Tektronix DPO 4104 series oscilloscope for a measurement.  When I start the measurement, the oscilloscope is in continuous mode.  During this period I want to adjust the vertical range of the two channels.  After that I will take the data using single acquisition.  In the programme, I am using Tektronix drivers.  Can I adjust the vertical range and offset using a knob or slides along with the channel configuring driver?  If yes, how?  Please help me.
Thanks in advance,
Meena 

Answer 1

I do not know how you are downloading your data from your scope. Scopes are typically 8 bits of precision, although when they average data the effective bits can increase.
So the data on the scope screen is typically an array of values from 0 - 255, (8 bit), possibly greater if someone averages the data, 0 - 65535. To get the real values in volts, you just do a linear transformation, ie, y = mx + b.
So in my program, I download the voltage values as an array of 16 bit words, in case someone decided to average the data. Along with that data, there is a header. The header contains a voltage offset, b in the equation above, and a scaling factor, m, in the equation above. Multiply and add the values to the array and you get an array of real voltage values. Also contained in the header is a starting time, a time increment, and the number of points. You can use these values to create the time array if it is needed.
The added advantage of downloading the data in this manner is that it is faster than downloading the values in ascii format.
So I would say, look at your program and see how the data is being downloaded.
Attached is a snippet from a program that converter the header and bytes from a HP54845A scope, I do NOT know whether your scope has the same format or not. But here is a description of what it is doing.
The data and header are combined in one data stream; earlier in the program I removed any ascii descriptions from the header so only numbers and a byte stream are being downloaded. The header data are parsed, and the byte stream is converted into signed 16bit integers in this case, then converted to real voltage values.
Hope this makes sense as I will be out of the office for a while and unable to follow up.
Cheers,
mcduff