Hardware Custom Device for HIL

[Ch.Sommer]

Hi all

I have some questions about the creation of a custom device. They are mostly questions of understanding.

We want to make some HIL-Tests with a System that has only DIO. The DUT run with about 1MHz but will be faster in the future. We want also to measure the switching time.

To realize this we want to create two custom devices. One will write and read the DIO’s and one will measure the time. So the first one should write down an Waveform or Array which was created bevor and write it each cycle out (so for example, the PCL runs with 1kHz and the custom device with 1 MHz the custom device will write/read 1000 states in one PCL-Cycle). For that, we want to use the PXIe-6547 HSDIO. So first, what type of custom device should we use? I have read some Guides about that but I am still not clear of it. The inline hardware is easy to use because of the channels and the state machine. But how can we write down an array of read and write commands? Also I’m not sure if the inline hardware custom device fits for systems where they should run faster than the PCL? Or is for that the use of a async device better? For me the use of a async would fit better but I’ve nothing found where there was a use of async hardware device.

I’m sorry if my English and explication isn’t very good but I need definitely some help to solve my confusions.

Any hints that point me in the right direction are much appreciated.

[HoussamK]

Hi,

an asynchronous Custom Device can run faster or slower than the PCL.

Depending on your requirements, you can create custom devices that run inline or in parallel with the PCL

An inline Cutom Device / Code cannot take longer than the NI VeriStand Primary Control Loop

Custom Device Types

[Ch.Sommer]

Hi HoussamK

Thanks for your answer. 

So did i understand that correct, that an inline custom device cannot be faster than the PCL? So our HSDIO can not work faster than the RT-System? So for my problem I’ve to take an async custom device?

I've found a lot of examples of inline custom devices for hardware, but nothing with an asnyc. Are the write and read vi the same or must I use different vi's?

Thanks a lot!

[HoussamK · Accepted solution]

Yes correct, the inline device cannot be faster than the PCL.

Your HSDIO could work faster, keep in mind that your HSDIO is a Hardware timed Module.

You can try working with an inline CD as long as your code don't take longer than the PCL

Yes, the write and Read vis are the same

[Ch.Sommer]

Hi HoussamK

I'm sorry for my late response.

Thank you for answering my question and your help!

I will try it with an async CD.

Cheers