Adjusting WaveForms display

[Mohammad Alsmadi]

Hello, 

I am using the ADP3450. I am wondering if there is any way I can start sampling at time=0sec or time=0min. I tried to manipulate the parameters in the "Time" window, but I could not achieve what I was looking for. As shown in the attached photo, the sampling did not start at time=0. Also, when I try to export the raw data, for Ch#1, for example, it shows that the first data point is recorded at t=-147sec as shown in the second attached photo. 

Could you please help?

Thanks,

Mohammad

[JColvin]

Hi @Mohammad Alsmadi,

Record mode (instead of Screen) will be able to achieve what you are looking for.

Within the Config option, you'll be able to set the number of samples to record, the sampling rate, the total amount of time to record (this is of course directly tied to the number of samples based on the selected sampling rate), and where you want the trigger position to be relative to your acquisition if you have a trigger.

By default, the trigger condition will be centered at the in the middle of the acquisition at the 50% point, naturally requiring the device to have already captured and stored 50% of the acquisition before the trigger condition occurs.

Setting the trigger point to 0% will let you start recording data as soon as the trigger is detected with no data prior to the trigger. If the Trigger condition dropdown next to the main record button is set to none (like mine is in the screenshot), it'll start recording data immediately.
If set to Auto, the system will look for the trigger condition within either 2 seconds or the total time the listed on the screen, whichever is longer, before automatically starting the acquisition.
Setting the trigger to Normal will have the system wait indefinitely for the prescribed trigger condition. If you have trigger mode set to Normal and some amount of trigger percentage (such as trigger position is 5% of the way into the capture so you have some data leading up to the trigger condition), WaveForms will be continually looping through that amount of prebuffer data to always have that 5% of data captured on hand for when the trigger condition finally occurs.

Let me know if you have any questions.

Thanks,
JColvin

[Mohammad Alsmadi]

Thank you, JColvin, for your answer. By using the record mode, I cannot see the acquired values on the screen until the recording is done, correct? Is it possible to see the values as they change while using record mode? 

Mohammad 

[JColvin]

Hi @Mohammad Alsmadi,

If you check the box for "draw while recording" you can see the values as they come in. My understanding though is that the screen will not automatically shift to continue showing the most recently acquired values, so unless your signal is changing at the idea rate when compared to the time division/total amount of time you can see on the screen, it will be difficult to effectively evaluate the data live due to the limited size , unless you only intend to zoom in on a particular section of already recorded data.

This will slow down the maximum recording rate possible for large amounts of samples, though as shown in the screenshot you will need to be recording at a several megahertz rate or have a larger amount of samples than you are able to store within the DDR memory (128 Mi samples or 134,217,728 samples as per the Buffer Size specification in the Horizontal System for the Analog Inputs, https://digilent.com/reference/test-and-measurement/analog-discovery-pro-3x50/specifications#analog_input_channels) before hitting that limit.

Let me know if you have any questions.

Thanks,
JColvin