Two question about running speed in Labiview RT and FPGA

[jiemo]

hi All

Right now I am working on a project, which need to be developed on Labview RT and FPGA

Here I have two quick question.

1. Why sampling rates of RTD (9217) module is very slow, it is just aroud 1/sec? even I just tried to run Labview example.

2. We would like to develop another HMI, which can be used for monitoring the program running in CompactRIO.  In my project, i want to use network publish varible to implement this function. but the running speed become very slow, when I put these variable into my codes. (Shown in attachment) 

Thanks

Regards

[Matti_Autioniemi]

Hi,

You are probably using high resolution mode which has a conversion time of 200ms/ch => 800ms/4ch. Try switching to high speed mode and you should be able to get conversion time of 2.5ms/ch => 10ms/4ch.

- Matti

[jiemo]

Thanks.

But it seems that "High Speed" and "High Resolution" is just for Theromocouple, not for RTD, right?

Does anybody have any idea about my second question??

Why the running speed is very slow, when I tried to use Network publish variable?

Thanks

[Matti_Autioniemi]

Nope, those modes can be selected when using 9217. Drop an I/O property node to your FPGA block diagram and select correct module from the list and you should be able to set conversion time.

Answer to your second question is that your shared variables update only when there's data available from FPGA. This means that if you use high resolution mode (800ms/4ch) they update once every ~800ms. Changing your conversion time to high speed should give you a faster update rate.