Using Core Functions on NIFB

[RCoutinho]

Hello!

I'm using the NIFB Library to connect Fieldbus. I was try to use the Core Functions (ReadBlock and WriteBlock) with the BLOCKTAG.PARAM.
I load the NI-FBUS Communicator Manager and open a session (using the OpenSession function). But, if I don't execute the NIFB Configurator before the application, that functions doesn't work. That problem accours with the Dialog application too.
Anyone knows what the problem?

Thanks,
Roberto Coutinho

[S.G.]

Hi Roberto,

Which version of NI-FBUS Communications Manager you are using? I guess you mean "Read Object" and "Write Object" functions when you were talking about "ReadBlock and WriteBlock", right?

In fact, we are able to call "Open Session" first in Dialog, and able to call "Read Object" with BLOCKTAG.PARAM successfully. No matter whether the Configurator is launched or not, the parameters can be accessed properly in Dialog Utility. By the way, we are using the latest 3.1.1 version.

What kind of FF devices you are connecting to?

Sean Gao

[RCoutinho]

Sean, thanks for your reply!


The function in the Dialog Utility is "ReadObject". I'm using the 3.1.1 version too.
I'm connecting a Smar FI302 and IF302 (4-20mA / H1 transducers) on a Softing FG-100 FF/HSE linking device.

If I use  the Administrative Functions (open link, open device, open vfd, open block) before, the ReadObject and WriteObject functions work without problems. When I try to connect with only a Session descriptor, it doesn't work. I think it's like "mapping" the Fieldbus. But there's no information about that in the NIFB documentation.


Roberto Coutinho

[S.G.]

Roberto,

You are right, NI-FBUS CM works more like a "passive" server, it will not actively scan/update the fieldbus network until it receives I/O function calls from Client applications (like Configurator).

In your case, you will have to call nifOpenBlock to open the corresponding block first, then call nifReadObject to access the specific parameters.

Thanks,

Sean