how to configure modbus using LabVIEW?
in [LabView]
|
Prev: Sudoku
Next: Labview 6.1 vi's for NI USB-8451
From: Srinivas Kharsada Patnaik on 15 Dec 2005 00:10 Hello Mr. Nishant, ya I got something what you said.but I could not make out one thing. Our purpose is to read the data from the COM port and check the redundancy.if there is no tarnsmission or communication error then just write the data in desired output port.Am I right Sir...? but how can we do CRC check?is there any predefined method or vi...?even i dont know how to pass the query. one more thing sir,what is the function of MBwaitForSerialRegister.vi? Thanks
From: pincpanter on 15 Dec 2005 04:11 Thank you guys for your help, but I'm searching a Modbus driver on the slave side. There are commercially available, but they are expensive, compared to the limited use I would do. Thank you anyway, this forum is a great resource and I learned a lot here since I started developing seriously with LV, one year ago. Paolo
From: Nishant on 15 Dec 2005 05:11 Dear Mr. Srinivas, Let us become friends first, instead of you call me sir. Here you can do is to just put the parameters which are required, like No of registers, protocol start address, modbus slave address, Modbus function etc. now take all these parameters and generate a CRC for that, to generate the CRC, the VI is given in the MODBUS driver, and MBwaitforserial register is not used anywhere, uptil now, may be it will come in use afterwards, i dont know much more about that, whenever you generate a query, generate a seprate query in each case and whenever u take the reply, take it seperately, in individual case, so it doesnt clash the modbus function and main thing is the case is drived by the modbus functions like 03:Read output Reister,16:Write multiple o/p register etc. and make the sequential case structure, for clearing the port, sending the query and taking the response form the device. i think which helps you now. Thanks, Nishant
From: Michael C on 15 Dec 2005 13:40 HI everyone, There is a Modbus library for LabVIEW 7.1 available from our website: <a href="http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71&p_node=DZ52363&p_source=External" target="_blank">http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71&p_node=DZ52363&p_source=External</a> Unfortunately, I don't have a version that will work on older versions of LabVIEW, but I do have a workaround if you need to install this library in LabVIEW 8.0. The above installer installs the two files zipped and attached below. Make sure that LabVIEW is closed before installing. The nimodbus.mnu file can be manually placed in the following folder:C:\Program Files\National Instruments\LabVIEW 8.0\user.lib\ The NI Modbus.llb library file can be manually placed in the following folder:C:\Program Files\National Instruments\LabVIEW 8.0\vi.lib\ I encourage any one interested in further Modbus development to visit <a href="http://sine.ni.com/apps/utf8/nicc.call_me" target="_blank">http://sine.ni.com/apps/utf8/nicc.call_me</a> and submit product feedback so that we can get a feel for your interest in the Modbus protocol. nimodbus.zip: http://forums.ni.com/attachments/ni/170/156996/1/nimodbus.zip
From: Nishant on 15 Dec 2005 23:10
Thanks Michael, I want to ask that, is this only works on LV8, coz we have the LV7.1 & i haven't tried it, so please help me. Thanks, Nishant |