Tensile Force Measurement captured by LabVIEW VI via MODBUS

Digital force test system with computer interface

Force Test Stand with integrated meter

National Instruments LabVIEW Modbus VI is modified to set the speed of the DFTS5000i test stand, initiate the test from event (mouse click on start button), then capture the force measurement from the panel meter, displaying values in real time on the simulated chart recorder.

The panel meter and motor drive each have a RS485 serial port and can be configured to use either ASCII or RTU (Binary) Modbus protocols. In this instance RTU is used for its increased efficiency (hence speed), each port is a slave on the bus controlled by the master port on the laptop. As the laptop does not have a RS485 serial port, it is simulated via a USB to Serial (RS485 version) Converter which windows presents as a virtual serial port available to the LabVIEW software.

 

Modbus VI Program Block Diagram

Modbus VI Block Diagram