sampling FP-1600

[porzio]

I had in my laboratory an FP-1600 with several modules connected by Ethernet (100Mbps) to my PC.

Now I have to measure pressure (very fast event) and I would like to know the sampling capacity of my system.

From the digital input I have to my PC what's the minimum sample I can measure? 1ms, more, less?

Giancarlo Porzio

[AlessioD]

Porzio,

the fastest sampling rate when using FieldPoint devices is determined by the Maximum Update Rate of the FP Module you are using. This is specified on the Oparting Instructions of the FP Module (e.g. FP-AI-100). You want to make sure you know how Ethernet Fieldpoint works. Basically when running a FP application you have 2 players:

- The program running on your PC

- The Fieldpoint Controller

When data is sampled by the modules it gets transfered over to the FP Controller. This is then transfered over the ethernet to the Host PC only if it has changed. This is done to reduce ethernet trafic. This implies that, no matter how fast your application loops and calls the FP Read function (1 ms windows resolution) it may retrieve the same data point over and over again until it has actually changed. Transmission of data over the ethernet is not deterministic in time, it depends on different factors, traffic being the most important.

It may become more interesting for your application to take advantage of Realtime Fieldpoint Controllers. In this case the control application resides aboard the FP-20xx and there is no need to transfer data over the ethernet. This means that when the channels are sampled, values are immediately available to the application which can use it to perform whatever action is needed.

Here is an interesting document about the Architecture of Fieldpoint in general.

Regards,

AlessioD