how to use NI 9401 and NI 9215 at the same time

[delcasmx]

IM using a NI 9401 to trigger an external circuit

and I need to read the response form it with NI 9215 almost immediately

IM having problems to sync the out signal and the Input one

the problem is that when the analog signal starts to record the efect i want to measure already happened
is there a way to start recording with NI9215 earlier?

I have tried with daq assistant only and in unsure how to do it with daqmx

thank you very much

[G_Lo]

delcasmx,

I have attached a screenshot of a similiar architecture that you could utilize with lower level DAQmx VIs.  Basically, you would have to place the DAQmx Start.vi for the Input before that of the output.  This can be done by wiring the error cluster to control the data flow.  You may also want to use a reference trigger in which the output triggers the input of the other card.  Instead of taking only post trigger samples, you could also obtain a certain amount of pretrigger samples to ensure that you do not miss your signals.  I have also included two documents which will provide more details into pretrigger samples. 

Waveform Acquisition with an External Trigger and Pretrigger Scans

pretriggering