Use pulse instead of clock to sync analog task and digital input

[kphite]

I need help. I found example code here: https://forums.ni.com/t5/LabVIEW/linearity-testing-ADC-using-PCI-6289/td-p/286924/page/2  (see ADC_test_2. vi) and it seems close but my application is a little different.

I have a pulse from my device under test that initates the start of the ADC conversion and then another that indicates the conversion is finished. I want to start  the first step in a linear ramp with an Analog output channel on the ADC start conversion pulse and then acquire the ADC outputs with the digital input lines for a configurable number of times and then stop and continue on to the next step in the ramp and repeat. I will need to count the number of end of conversion pulses so that the ramp can continue when the configurable number is reached. I'm using a PCI-6259 M series.

[WillMck]

kphite, 

Have you tried editing the example code from the referenced forum post? 

What specific problems are you seeing, as in what have you been able to accomplish thus far? 

So far, I understand you need to accomplish these four steps: 

1). Start the first step in a linear ramp on the first conversion pulse

2). Acquire the ADC outputs for a configurable number of times (Finite acquisition?) 

3). Count the number of end conversion pulses. 

4). Retrigger the sampling for each ramp. 

What desired behavior from your application have you been able to get working? 

[kphite]

BIGMAC,

Thanks for the reply. I actually don't have anything working yet. Honestly, I'm confused on how to configure this instrument.

My updates are shown below.

1). Start the first step in a linear ramp on the first conversion pulse
 (This can actually just be the start of the task. The ramp needs to be configurable from one start voltage to and end voltage).
 

2). Acquire the ADC outputs for a configurable number of times (Finite acquisition?)
 (Finite Samples should be correct)
 

3). Count the number of end conversion pulses.
 (There is an end of conversion pulse from my device that will be read on a digital input line. This should also trigger the ramp to increment to the next value. I will need to count these pulses to keep track of my number of conversions)
 

4). Retrigger the sampling for each ramp.
 (And repeat steps 3 and 4 until the end of the ramp is reached)

kph

[WillMck]

kph, 

If I understand your application correctly, you can start the first step of the voltage ramp (voltage output task) on a trigger from the device and set the trigger to respond to a pulse from the device under test. 

Try taking a look at this example: https://forums.ni.com/t5/Example-Code/NI-DAQmx-Retriggerable-Analog-Output-LabVIEW/ta-p/3996084 - DAQmx retriggerable analog output. 

Retriggerable Tasks in NI-DAQmx: https://www.ni.com/en/support/documentation/supplemental/21/retriggerable-tasks-in-ni-daqmx.html

Retriggerable Acquisition: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MXxSAM&l=en-US

There are also some links at the bottom of that page that might prove helpful. 

You mentioned that there is an end of conversion pulse from your device "I have a pulse from my device under test that initates the start of the ADC conversion and then another that indicates the conversion is finished." 

You can easily count these pulses using one of the counters on the PCI card. Take a look at the "Counter - Count Edges" shipping example. 

[kphite]

BIGMAC,

For my application I believe I will need DAQmx retriggerable analog output and retriggerable digital input. I'm having trouble understanding how to do both where they are synced together with an input trigger.

[WillMck]

kph, 

What steps have you tried thus far?