writing to a profibus network using labview datasocket

[Bow]

Hello

Can anybody help me?

I'm trying to control a moeller inverter using labview datasocket on a profibus network. the problems i am having is how to structure my Vi to write the message. so far i have used loops to write the first message to notify the inverter of status change then to write the new frequency setpoint. but i am having awful trouble doing this consistently without the inverter sending a fault message and denying me further control. i have also used an update button to pass the next value on but this requires furious mouse clicking to eventually get the message to the inverter. i have tried modifying some of the labview examples for CAN write and some others but often with less success. i'm sure this must be a standard thing with any Profibus writing to any other equipment. Can anyone give me any pointers or example code to help.

[SachaE]

Hi,

I'm assuming that since you're going over datasocket, then you're linking to a profibus opc server.

For OPC in LabVIEW, LabVIEW Datalogging & Supervisory Control (LVDSC) module is the way to go. LVDSC is an add-on module which you can install on top of your LabVIEW. It provides native (non-datasocket) OPC support. In addition, it also provides features typically required by a datlogging and supervisory control application, like historical logging and trending, alarming, security, etc. Check it out:

http://sine.ni.com/apps/we/nioc.vp?cid=10418&lang=US

With either datasocket, or LVDSC, you're looking at a polling setup, and the actual communications is done with the Profibus OPC server. In this way, if you're writing to quickly, or the poll rate isn't correct at the server side, then that could lead to problems.

I would recommend contacting both the OPC provider, and the device manufacturer to see if there's any quirks in the system you need to be aware of, and create your code appropriately.

Another option might be to take on already developed drivers and hardware. There is a company in Germany offering VISA drivers for Profibus communications (www.comsoft.de), however, they're linked to specific profibus interface cards. This is not a personal or a National Instruments recommendation however, but something another user has posted on a similar discussion forum so we can't be held responsible if you decided to go down that route.

http://forums.ni.com/ni/board/message?board.id=120&message.id=224&requireLogin=False

Thanks

Sacha Emery
National Instruments (UK)

Message Edited by SachaE on 01-31-2006 01:35 PM

[jiujiulong]

Socket and CAN is different communication way.

Socket is a share a file comunication and CAN is a net bus.