Machine & Process Control Case Studies

 Control software development for bespoke test rig

When a leading technical university embarked on the development of a custom built Tensile Tester they were keen to keep to a minimum the effort needed to develop the control system.  They opted to use a combination of LabVIEW with a CompactRIO (cRIO) programmable controller from National Instruments to meet the dual requirements of high performance hardware and rapid robust code development.  The software development was contracted to Product Technology Partners (PTP) and was completed in less than a week, even working from scratch.  Key features of the system include:

  • Pull wire drive to drive the moveable carriage via a load cell
  • cRIO chassis with 4 modules (thermocouple, strain gauge, TTL digital I/O and servo controller)
  • Positional closed loop motor control
  • Real Time software deployment with FPGA
  • Software based secondary safety circuit
  • Simple but intuitive User Interface
  • Data logging & analysis with graphical presentation

 Control system for manufacturing test system

Our customer was looking to automate a manual test rig which was being used in a manufacturing environment. The key objectives were to reduce test time (thereby increasing throuhgput) and de-skill the operator involvement. PTP developed a PC application running custom software and using National Instruments' data acquisition cards together with bespoke electronics, mechanical items and cabinet. As the design of the Device Under Test (DUT) had not been finalised before the project outset, the software had to easily configurable to allow the customer as much flexibility as possible. The ability to modify the test flow and pass criteria meant that production testing could be carried out with some level of continuity as the DUT evolved. The test rig was ultimately transfered to a high-throughput production facility in China and PTP was involved with the training and handover to the new production team.

 Instrumentation control for pharmaceutical application

A leading instrumentation manufacturer was planning to launch an update of one of their pharmaceutical products and wanted to use the opportunity to completely renew the PC support application at the same time. PTP was involved with the project from the outset and participated in the design and specification of the application as well as doing the final coding and testing. The custom-designed solution was developed in Microsoft Visual Studio and was connected to the instrument via an RS232 link using a bespoke communications protocol. The application was designed to allow the user to create a "recipe" that controlled the variable parameters of each of the individual stages of the processing cycle. The graphing system was optimised to enable the user to receive instant visual feedback of how the recipe is progressing. The final system requirement was for the application to support older versions of the instrument to allow "retro selling" of the upgraded software.

 Control software for pharmaceutical device manufacturer

PTP was contracted by a specialist machinery manufacturer to develop the control system for an automated machine to test the operation of medical devices. The application had to incorporate a great deal of flexibility to enable testing of a number of different device types, both during device development and for pre-production proving trials.
The control solution incorporated both an embedded system for the machine and a PC based application to provide operator controls, machine monitoring and data presentation & analysis facilities. As the test machine was of innovative design, a significant element of R & D was required in the software development to provide a number of novel features including:

  • development and implementation of an application-specific scripting language to enable the operation of the test machine to be customised to suit the different devices under test and the different circumstances in which they were to be tested
  • development of a novel User Interface that enabled both control and monitoring of the machine, together with easy intuitive editing, storage and retrieval of the test scripts.
  • development of the data capture and signal processing algorithms required to derive high-accuracy measurements from a novel measurement mechanism inplemented in the machine
  • high accuracy slow speed control of a precision servo motor, with torque monitoring facility

 Windows Mobile PDA development for instrument control

An established pharmaceutical instrument manufacturer was looking to develop a portable, hand-held controller for their multi-cell reaction vessel. PTP were contracted to develop a PDA-based application which could remotely configure, control and log data from the reaction vessel. The key features of the development included:

  • analysis of end customers' requirements
  • intuitive and stylish User Interface design
  • low level communication with the reaction vessel using customer bespoke protocol
  • application development for multi-functional control (heat, cool, hold, stir, sample, dilute etc)
  • data logging, Real Time graphical presentation and trend analysis
  • recipe creation "wizard"
  • event scheduling and conflict handling
  • simulation software to allow testing and trouble-shooting in the absence of hardware (which was still in development)

The development was carried out in Microsoft Visual Studio with the PDA being connected to the reaction vessel via a Compact Flash-to-Ethernet converter.

  Control System upgrade

A metal processing company had three computer-controlled knitting machines for metal wire. All three machines were of considerable age and had become unreliable as time passed. This unreliability stemmed from the embedded computer hardware that formed the core of the electronic control system - specifically, the processor card, hard disk drive and LCD operator display units. The remaining electronic, electrical and mechanical items were regarded as realiable and/or maintainable. In order to avoid the cost and disruption of a completely new control system, PTP was contracted to replace the unreliable items, modify the machine operating software and refurbish the control cabinets. The project carried substantial risk because of the difficulties of trying to find modern replacements which would function in a similar manner to the old hardware items and required PTP to design and build custom interface boards for the three machines.

 Low cost, high reliability Servo-Hydraulic Control

Precision servo-hydraulic control is difficult and expensive to achieve using conventional controllers. PTP recently completed a design study for the replacement of conventional control hardware with a custom controller based on LabVIEW FPGA technology. In this successful project, we demonstrated the substantial savings in hardware cost and software development time that can be achieved, as well as the considerable opportuntiy for performance enhancement through the implementation of advanced control designs.

Full article available soon

 Control Systems Design
An internationally renowned metals manufacturer required a control system for an experimental 100 tonne hydraulic press used for testing the forming of sheet metal under controlled conditions. We worked with mechanical, hydraulic and electronic designers to specify and implement a controller for the press that uses high-speed hydraulic servos to provide precision control of the machine to follow pressing cycle profiles specified by the research engineers.

 

Other case studies to be added soon!