RS -485 Test in cFP 2020

[kkronline]

Hai Marni,

Kindly Clarify this also, In the cFP 2020 manual, it is mentioned that " If you are not running an embedded application, you must target the cFP-20

xx in order to access the serial ports."

The VIs sent by you,Whether  will take care of the 4 serial port test (includes Three RS232,  RS485). I couldn't locate about serial port in the MAX. The configuration of cFP2020 in MAX means "setting the IP, Find Devices only". If anything more to configure, figure it out.

In the VI Guide lines "Modify the Fieldpoint IO Point constants on the block diagram to match your IP configuration", IO point means ?

I am going to short (2 and 3) for RS 232 (port 0, port 1, port 2)       &          (7 and 3) (2 & 6)   for RS 485 (port 4).

I hope it is enough to test the cFP ports with ur VIs.

I attached the VI for reference.

Thanx in advance

Karthikraja

[Graziano]

Hi kkronline!

  I'll try to answer, as I can....

  IO points are like paths, they're used to locate, for example (in your vi too) the cFP LEDs. I highligted them with a red circle, in the attached file.  You have to set IP address according to the address you gave to your cFP in MAX.

   More, I would suggest you to build your own example, to implement an HyperTerminal between your PC and your FP module, in which, say, you send via rs-232 one string to your cFP, and your cFP switch on A LED when this string is received, ore something like this.....

   Please, let me know if you encounter further troubles!!!

graziano

[Jeffrey_P]

kkronline,

To clarify the line about the serial ports on your FieldPoint module:  if you embed your code onto your cFP module, then you have direct access to the serial ports on the cFP module.  If you are not embedding your code, then you have to "target" the cFP module from LabVIEW.  However, you will not have full access to the serial ports in this manner. 

-Jeff P

[Khalid]

Hi Jeff,

You wrote:

"If you are not embedding your code, then you have to "target" the cFP module from LabVIEW.  However, you will not have full access to the serial ports in this manner. "

I am not sure I understand this.  Why won't we have "full access" to the serial ports when targeted?  Isn't a targeted VI really running on the controller (same as an embedded one) -- only difference being the added functionality of interacting with it on the host VI?

Thanks,

-Khalid

[Jeffrey_P]

Khalid,

http://digital.ni.com/public.nsf/websearch/6AC8559FCE42211886256B8E006DEB60?OpenDocument

This is a good resource.  It is one of our Knowledge Bases that discusses the serial ports on a FP controller.  There are also other documents linked on this page that might be of use as well.  Hopefully this will explain it better than I can!

Happy Holidays!!  Jeff

[Khalid]

Hi Jeff,

Thanks for the prompt response!  The KB article doesn't say anything about not having full access to the Serial ports on a cFP from a targted VI.  I understand that these cFP-Serial ports cannot be accessed directly by a _non-targeted_ VI.  But, I don't think targeted VIs (just like embedded VIs) should have any problem. 

I shall get back after some tests of my own.

Thank you for your Support.

-Khalid

Message Edited by Khalid on 12-29-2005 03:03 PM

[kkronline]

Hello all

In cfp_serial_test_visa.vi, what should be filled for VISA resource name, It is listing only the PC's com and LPts. For testing the RS-485, what i have to fill.

Wishing you a very happy  and Peaceful new year

Thanks in advance

Karthikraja

[Khalid]

You can use "ASRL4::INSTR" to refer to the 485 port (COM4) on the cFP-2x20. 

Regards,

-Khalid

[Travis G.]

Hello Everyone,

I'm writing this post for the sake of future reference and clarifying a few confusing points touched on this thread.  When working with FieldPoint or Compact FieldPoint Network Controllers, targeting a program to the controller is synonymous with embedding a program onto that controller.  In fact, if you target a network controller and deploy a VI to it using the run button, you can disconnect your development machine, your program will continue to run embedded on the controller.  Embedding, or targeting, a program to a [c]FP Network Controller requires the LabVIEW Real-Time module.  This module allows you to target the IP address of the network controller, compiles your program into an executable capable of running embedded on that controller, and downloads the program to the controller's onboard memory.

Without the LabVIEW Real-Time module, the only way to programmatically interact with a [c]FP Network Controller is through the FieldPoint Driver API, i.e. the FieldPoint Express VI or the FieldPoint Read/Write VIs.  These VIs allow you to 'subscribe' to the data being served by the network controller.  These methods use what is called a FieldPoint IO Point, which is basically a network path to a specific channel of data that your host machine can subscribe to.  These methods don't deploy or embed any actual programs to the network controller.  All of this can be done without the LabVIEW Real-Time module, just using the FieldPoint driver and API.

The only way to access the serial ports a [c]FP-20xx Network Controller is by embedding a program onto the controller, and in that program accessing the onboard serial ports of the controller.  Since embedding, or targeting, a program to the controller requires the LabVIEW Real-Time module, so does serial communication.  The easiest way to program serial communication is to use the NI-VISA driver API.  This requires that the NI-VISA driver be installed on the [c]FP-20xx Network Controller, which can be done through Measurement & Automation Explorer (MAX).  Under 'Remote Systems' in MAX, find your networked [c]FP-20xx and expand the software category.  By right-clicking on 'Software', you can easily Add/Remove Software on the [c]FP-20xx.  Make sure that the latest version of the NI-VISA driver is installed on the network controller.

The cFP-2020 contains four onboard serial ports, three RS-232 and one RS-484.  There is a VISA alias associated with each port, from COM1 through COM4.  These ports also have a second VISA alias titles 'ASRLx::INSTR' where the X is the COM number of the port.  Check the cFP-20xx and cFP-BP-x User Manual for more information about each port.  You can use either the Com names or the ASRL::INSTR names to access the ports using the VISA Read and Write VIs.  When you target your program to the cFP-2020, your program runs embedded on the controller and the COM port VISA accesses is local to that controller.

I hope this clears things up and I apologize for the long-winded reply.

Regards,
Travis Gorkin
Applications Engineering
National Instruments
www.ni.com/support