async data acquisition with external trigger

[Bendiksa]

Hi, I am having problems with reading a single sample on the event of an external trigger signal from a velmex vxm stepper motor controller. The vxm controls an xy-table, consisting of two slides. The controller can be set to output pulses every #no. of motor steps. I want to use these pulses to trigger a voltage acquisition on a DAQPad 6015 system (one sample every # pulse from the vxm).

The voltage signal come from a sensor looking at laser reflections from an etched silicon wafer surface. I am mapping the reflection signals on an intensity chart. The pulse train coming from the vxm is thereby async, and it is important that the sampled data from the laser sensor has the correct/ same distance in steps between them.

I guess I'm looking for some example code or similar. Until now I've only found code that samples a huge amount of data on the first pulse (in every direction) from the vxm. The pulse width can vary in size from 10us to 2ms.

Hoping for an answer to my problems

Kind regards, Bendik

[DFGray]

You should be able to use the motor controller pulses as either your sample conversion or master clock.  You can also use it as a simple digital trigger and only take one sample per acquisition.  The DAQ Assistant can generate sample code for you that will set this up, if you cannot find another example.

Let us know if you need more info.