LabVIEW VIs make light work of solar simulation motion system

Arcus Technology is represented in the UK by LG Motion.

Arcus' customer required the retrofit for a laboratory solar device test rig that was originally built using LabVIEW measurement tools but had a disparate motion system with limited features that restricted the overall rig’s performance capabilities.

The upgrade required improved control of apertures that adjust the intensity of individual light sources to allow multiple beams to be paired and coordinated in various sequences to provide higher level analysis.

The design brief called for a motion system that included LabVIEW VIs and USB communications as key requirements of an economic control system that would maintain the existing drive and stepper motor components.

Whilst other motion system manufacturers supply NI LabVIEW VIs, many were considered far too costly and sophisticated or were servomotor based - which would have necessitated the expensive and unnecessary replacement of motors and drives for the 9-axis system. A combination of Arcus’ USB networked PMX-4CX-SA, 4-axis stepper motor controllers and the free of charge LabVIEW VI library was chosen for low cost, ease of installation and simplicity. 

The LabVIEW VI library is available with all Arcus USB products and is supplied with source code and installers that make set-up and programming straightforward for the customer. The driver set consists of low-to-high level VI's designed for both simple and complex motion and I/O control solutions; offering a very cost effective option when using single or multiple axis stepper  motor systems with NI LabVIEW measurement or control applications.

An intuitive LabVIEW VI based ‘Utility Panel’ is also supplied as part of the package which makes use of many of the features available and can provide the basis for application development. The Utility Panel also demonstrates entry of Arcus’ user-friendly BASIC-like A-SCRIPT programming language that may be additionally used for programming. Both the LabVIEW VIs and A-SCRIPT can be used by non-experienced programmers.

Arcus’ PMX-4CX-SA, is a basic 4-axis stepper motor motion controller with USB 2.0 and RS485 communication which supports multi-task A-SCRIPT programming. It features a 400kHz maximum pulse rate output to suit microstepping motors at moderately high speeds with trapezoidal acceleration and deceleration profiles for smooth ramping and start/stop performance.

As well as open collector pulse and direction and enable outputs, the DMX-4CX has a complement of opto-isolated limit and home switches with 4 inputs and 4 outputs. From the same product series, the PMX-4EX-SA adds encoder feedback inputs to allow the controller to automatically monitor and maintain stepper motor position through A-SCRIPT software commands. The controller may also be used to control digital servo drives.

Arcus’ competitively priced product range also includes the DMX series integrated stepper motor + drive + motion controllers with a built-in microstepping drive and optional incremental encoder interface that provides closed-loop feedback for automatic position correction.

The DMX series is available in NEMA 17 and 23 frame sizes as well as a NEMA size 11 version with a square section of only 25mm x 25mm. These products illustrate Arcus’ strong product design and very competitive pricing, and are available with a wide choice of communications interfaces including USB 2.0, RS485, Ethernet and Modbus and CANopen.