LabVIEW vi communication with MODBUS

[RavensFan]

Don't use the Modbus Init.vi.  You really don't need it.  It has the stop bits hardcoded at 1.

Just open it up and look at it.  Mostly, it just does the same things that the Serial Port Configure VI does.  Just use that and set all the serial port settings to what you need.

It doesn't even set the device ID like you said.  There is a separate connector terminal on the MB WriteRead.VI that defines the slave address.

[Chris_P_SD]

Good call, thank you Ravens Fan.  Now, if I could just get it to not time out...

[ing_arr]

Hola Himanshu_Goyal:

Estoy haciendo una aplicacion en Labview para comunicar via Modbus una serie deanalizadores de redes electricas.Si es posible necesito el ejemplo ModBUS.vi y la libreria NI Modbus.llb q le mandaste a Ksurdi, pero en la version 8.5.Saludos:

ing_arr

[ing_arr]

Hello Himanshu_Goyal: I'm making an application in LabVIEW to communicate via Modbus series of network analyzers electricas.If may need the example ModBUS.vi and Modbus.llb NI library  you sent him Ksurdi q, but in version 8.5.

[Eric-M]

Hi ing_arr,

The MODBUS Library for LabVIEW should work in 8.5 for you.

[Hong.Zhang@agresearch.co.]

Hi all

I am using MODBUS as well. I have got respond value in 4 bit Hex string, dut how to convert to floading number?

ex: 0D444104 = 8.2532, 00004248 = 50.0000, B9684092 = 4.5851

Please help.

Thanks

Hong

[thibber]

Hi Hong,

I think that this forum will answer your question:

https://forums.ni.com/t5/LabVIEW/Convertion-Hex-String-to-32bits-Decimal-floating-point/m-p/412772?q...

[routcha]

Hello all
i m asking how i can download data from a datalogger working as master using the modbus lib 
Thanks

bilel

[alcava.cr]

Hi routcha,

When you say "download data from a datalogger" seems like you need a FTP more than a Modbus connection, modbus is simply another communication protocol. Please take a look at the examples that comes with the library in case they can help you, if not, consider opening a new thread.

[4D73R]

Hi all,

I'm having problems with MB Serial Example Master.vi from the NI Modbus.llb.

I have connected my DTE with another DTE via RS-232 and Ethernet cable. Primary communication is through TCP/IP, secondary (ModBUS) via serial cable.

Both, device and my PC are added in project. On one device I ran MB Serial Example Slave, and on other MB Serial Example Master. 

The problem is, when I write in registers from slave, slave and master can read it. But, when i write in registers (holding or coils) from master it is not working.

I tried the same with TCP examples and it worked.

How could it be?