DMC’s client required their existing system to be upgraded as it was approaching end-of-life. The client’s calibration lab did not have any additional backup systems, so it became a priority to modernize and replace the current system. We developed a mobile calibration test stand that can be used to calibrate pressure, force, and torque transducers.
The test stand is capable of integrating with external measurement equipment over USB, GPIB, serial (RS-232), and Ethernet, allowing test sets to adapt to future calibration requirements. Additionally, the calibration test stand features several extra PXI slots, allowing additional instruments to be added as test requirements change over time. The mobile calibration test stand is approximately four feet tall, two feet wide, and three feet long.
The system’s condensed size allows it to easily traverse through doors and move from building to building to access a diverse set of equipment and sensors it is responsible for calibrating. In addition to designing and fabricating the hardware, DMC also created a custom LabVIEW application to view and monitor live data, record data, and generate a calibration report.
3D model of the mobile calibration test stand
DMC’s Fabrication Studio team assembled the mobile calibration test stand in-house
Custom Hardware
DMC designed the custom front panels that secure the programmable power supply in place and provide a mounting surface for DUT and auxiliary connectors to plug into the system.
DMC designed a custom PCB mounted on the inside face of the bottom panel. The purpose of the PCB is to route signals and simplify the system’s internal wiring. This PCB was designed in-house by DMC’s Embedded Development team.
Plan for the Future
The system was designed with the future in front of mind. It was important to the client to be able to adapt to new products and changing test requirements. To help achieve this an 18-slot PXI chassis was used in the system allowing several slots to be reserved for future use. The system interface was designed to allow for maximum adaptability. Banana connectors allow the client to connect to DUTs or external test equipment with non-standard interfaces and the bulkhead USB, GPIB, serial, and ethernet (RJ45) connectors allow the client to connect new models of measurement equipment across most commonly used communication protocols.
In addition to the hardware, the LabVIEW software was designed in a way the client could expand beyond the original project scope and add support for new calibration measurement devices by using a hardware abstraction layer (HAL) and measurement abstraction layer (MAL). The HAL and MAL help simplify future code additions, allowing the client to maintain complete ownership of the codebase after its initial deployment.
Built In-House
Our Control Panel Design and Fabrication team from the DMC Fabrication Studio built the test system in-house. The enclosure encompasses a rugged 14U rack system, which allows the PXI chassis, power supply, custom signal routing PCB, and DUT interface connectors to be easily mounted. A lockable shelf at the top of the rack provides storage space for the system laptop and any testing accessories while not in use. Large rubber casters allow the system to roll indoors and outdoors to service different buildings throughout the client’s campus. The external DUT and auxiliary device connectors are secured to the front face plates, while the measurement and switching equipment are slotted into the PXI chassis near the bottom of the rack.
Conclusion
DMC leveraged the expertise of many of our service areas to design, build, and deliver a new and improved calibration system for the end client. The Test and Measurement Automation team led the overall design, the Embedded Development team designed the custom PCB, and the Control Panel Design and Fabrication team was responsible for the final assembly of the system.
The upgraded test system allowed the client to increase calibration efficiency, accuracy, and allow for room to expand the system’s capabilities in the future. DMC developed a LabVIEW application that can be expanded upon by the client and they are able to maintain complete ownership of the system after final delivery and acceptance testing.
Our extensive experience with LabVIEW programming, developing Test and Measurement Automation systems, and building turnkey solutions qualified us to deliver this modernized system and successfully upgrade the test equipment to meet the client’s present needs while making provisions to enable future enhancements.