Recording data on trigger for unknown time

[1113215]

hello,
I m using NI-5105 to acquire data on single channel using trigger.
I m using ch7 as trigger and recording data on channel 0, using my own (modifieded) version of the example "MultiRecordFetchMoreThanAvailaleMemory".
I hav acquired data on a trigger of say 10Khz i.e with known time for next trigger(so i can set the "Number of samlpes" to be acquired after each trigger).
>>Now the problem  is that if i want to record data on a trigger  whose inbetween interval is unknown , how can i program that??
>> I dont know how to set the "Number of samlpes" to be acquired after each trigger

seeking help

regards
Umair

[pBerg]

Howdy,

You can use niScope Configure Horizontal Timing to configure the number of samples to acquire after each trigger. Specifically, the min record length input to this VI determines how many samples you take after a trigger is reached. Collections of samples are organized into records. For example, if you acquire 500 samples after a trigger, then you have one record of 500 samples.

For more info, I'd reference you to the NI-SCOPE help file accessible within LabVIEW by navigating to Help»NI-SCOPE LabVIEW Reference Help.

[1113215]

pberg,
thanks for ur reply
but i think u didnt get me , I  have acquired data on trigger for fixed no. of samples after each trigger (of fixed interval),
but if trigger interval time varies like 10ms then 20ms then 30ms then 10ms and so on, how can i capture the all the data for this varying time interval

regards
umair

[samantham]

Hello,

 

There are many different way to configure a read or fetch, but most will require information about the number of record and samples per record.  One option to get away from supplying this information is setting up a continuous acquisition … like a fetch forever application.  This applied to your specific application would require acquiring the data on one channel and the trigger information on another channel.  It seems you are actually already doing this.  Some changes that will need to me made … The channel connected to the data line will run with a fetch forever setup.  There are examples that ship with the drive that utilizes this fetch setup of fetch forever.  So now we are acquiring data related to the data line and the trigger line on two different channels.  Then in software we can parse out sections of data related to each time varying trigger and write those sections to their own file. This would happen by comparing timestamps.

 Please check out some of the documentation in the NI High Speed Digitizer Help.  Some topics are Retrieving Data from the Digitizer to the Host Computer and Acquiring Data Continuously.