MODBUS Library for LabVIEW

Publish Date: Dec 17, 2014 | 130 Ratings | 4.38 out of 5 |  PDF | 47 Customer Reviews | Submit your review


The MODBUS library is a free, downloadable set of Virtual Instruments (VIs) that provide Modbus communication from any standard Ethernet or serial port. The LabVIEW library implements the Modbus protocol in software and offers both master and slave functionality. Using the Modbus library, Programmable Automation Controllers (PACs) can communicate with gateway devices that provide connectivity to a wide variety of industrial networks, such as PROFIBUS, EthernetIP, and DeviceNet.

Version 1.2 ( of the MODBUS LabVIEW Library is backward compatible with previous versions of the library.  It adds a set of polymorphic VIs that make it easier to use MODBUS commands.  These new VIs are also fully documented with a help file.  Comments have also been added to the examples.  Please follow the steps in the readme file for manual installation of the library.  There is no installer available at this time.

If you are new to MODBUS, this series of whitepapers serve as an introduction to the protocol. 

A newer library, intended as a replacement for this one, was added to This is not an official NI Product. 

Please note that this is an example program and not an official NI Product.  For a more complete, fully supported MODBUS solution, NI recommends the Modbus I/O Servers and Modbus API (2014 and newer) included in the  LabVIEW Datalogging and Supervisory Control Module.  

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Customer Reviews
47 Reviews | Submit your review

Response to Maik - Nov 3, 2014

@Maik, the reason slave address 0 is treated as broadcast is because this is defined by the Modbus protocol. This has nothing to do with the driver itself. If either of us had to write a Modbus driver, we would have to do the same just so we comply with the Modbus protocol.

 - Oct 16, 2013

Hi, I'm trying to run the example of the Ethernet Modbus feature. I created a *.vi containing only 'MB Ethernet Example' and another one containing only 'MB Ethernet Example'. I run the slave and the Master afterwards. After some seconds, I get this message : fszr.png I use LabVIEW 8.5.1. Is this version covered by this toolbox? Thanks

Very buggy - Oct 9, 2013

1. The Init VI handles all COM ports as true COM ports, but it does not work with VCOM. So I had to modify the serial settings init (first Visa Open, then Visa Serial Settings, not via property node) 2. There is no timing between Write and Read 3. Slave address 0 is considered as broadcast in the sub VIs, but this applies only for a serial line Modbus, which COM ports and Ethernet are not, because they're peer-to-peer. So the slave address 0 detection in the sub VIs is nonsense, because you can not make a broadcast with slave address 0 on P2P.

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NI MODBUS Library 1.2.1



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