Error -200284 from NI-SCOPE Fetch VI/Method

Issue Details

Solution

This error was returned because the timeout occurred before any samples were received. Below are some possible reasons for this error:

 

Adjust the timeout value:

If your sampling rate is low and/or your samples to read is high this may allow the time to elapse, returning an error. To correct this increase the timeout to accommodate the rate and the samples to read. The timeout value should be larger than the number of samples to read divided by the sample rate.

Verify that the reference trigger is configured correctly:

With NI digitizers, there are three different types of reference triggers you can use:

• Software Trigger
• Analog Trigger 
• Digital Trigger.

Note: There is a Timeout input for the NiScope Read or NiScope Fetch VI. Setting the Timeout to 0 allows you to fetch whatever sample are currently available. Setting the Timeout to -1 will bypass the timeout altogether.

Depending on which trigger you are using, there are different solutions to this error:

Digital Trigger:
A digital trigger will be coming through on PFI/RTSI/Trig line. Verify the following: 

• The trigger is operational and sending its signal properly through the hardware.
• The hardware can support the line on which the trigger is being sent. 
• The software session is looking for that trigger on the proper line.
• The voltage of the trigger source is within specification of the digitizer.

Analog Trigger:
An analog trigger occurs when the voltage on a specified channel reaches a designated value. Verify the following:

• The trigger has been properly configured (i.e. trigger source, trigger level, trigger slope).
• The signal appears correctly when an immediate trigger is used. This allows you to see your signal in real time so you can manually verify that the desired voltage is actually reached.

Software Trigger:
With a software trigger, the session will not fetch the data until the NiScope Send Software Trigger Edge function has been executed.

• Verify this function is executed within the specified Timeout value.

Additional Information

The timeout value specified in the NI-SCOPE Fetch method/VI works for the total number of records specified in the horizontal timing configuration. So for example, if you have set 500 records to be acquired and a 20-second timeout, all 500 records must be triggered and acquired in 20 seconds. Therefore, in this scenario, if your triggering signal is not fast enough to occur 500 times in 20 seconds, you will see this error.

In case you have a situation where the AC triggering is working for you but the DC triggering is not, then it is possible that your AC signal is fast enough to cross the triggering threshold 500 times (for 500 records) in 20 seconds (the timeout period). But your DC signal is not fast enough and does not cross the threshold for all the records in 20 seconds.

Therefore, make sure to adjust the number of records and timeout according to your application to avoid this error.