Development of a Standardized Flexible & Scalable Tester System Based on NI PXI & TestStand
Initial situation and project task
Due to changing requirements for manufacturing technology and because of a growing number of product variants Miele required a new generation of standardized test stands. These new test stands should be equipped with modern and world-wide approved software and hardware technology in order to guarantee long-time availability and scalability.
The implementation of a uniform tester concept allowing for testing of different product variants made up the primary requirement. In addition to that, a fast changeover from a single operator-dependent work station to an in-line system was required. In order to achieve this, a basic rollaway tester rack including exchangeable adapters and interfaces had to be developed.
At the same time, the system had to meet the following requirements:
Implementation and challenge
During implementation, special emphasis was put on the design of the interface, which was expected to become a bridge between the new standardized test stand and the product specific adaptors. Modular configuration, minimization of the required wiring and usability for devices under test providing a high number of channels have been among the decisive criteria for the tester’s design.
In order to reduce wring, a switching matrix, consisting of a multilayer PCB (4 layers) has been made the tester’s core element. The interconnection of the integrated components is realized via measurement and control hardware by NI and via modules by VPC, allowing for the connection to products by means of 978 pins. For the reduction of future costs, the interface has been designed modularly, so that the number of channels required for each test is defined by the device under test.
Due to the integration of technical components by NI, offering broad functionality and due to the excellent signal distribution for the switching matrix is was barely necessary to include further individually designed hardware components.
Due to changing requirements for manufacturing technology and because of a growing number of product variants Miele required a new generation of standardized test stands. These new test stands should be equipped with modern and world-wide approved software and hardware technology in order to guarantee long-time availability and scalability.
The implementation of a uniform tester concept allowing for testing of different product variants made up the primary requirement. In addition to that, a fast changeover from a single operator-dependent work station to an in-line system was required. In order to achieve this, a basic rollaway tester rack including exchangeable adapters and interfaces had to be developed.
At the same time, the system had to meet the following requirements:
- High number of measurement and stimulating channels (voltages up to 240V)
- Complex devices under test (including LEDs, displays, sensors, bus interfaces...) have to supported
- High number of products and product variants can be handled
- Modular adapter concept
- Parameterization instead of programming
- High flexibility, allowing for low design and implementation costs of new products
Implementation and challenge
During implementation, special emphasis was put on the design of the interface, which was expected to become a bridge between the new standardized test stand and the product specific adaptors. Modular configuration, minimization of the required wiring and usability for devices under test providing a high number of channels have been among the decisive criteria for the tester’s design.
In order to reduce wring, a switching matrix, consisting of a multilayer PCB (4 layers) has been made the tester’s core element. The interconnection of the integrated components is realized via measurement and control hardware by NI and via modules by VPC, allowing for the connection to products by means of 978 pins. For the reduction of future costs, the interface has been designed modularly, so that the number of channels required for each test is defined by the device under test.
Due to the integration of technical components by NI, offering broad functionality and due to the excellent signal distribution for the switching matrix is was barely necessary to include further individually designed hardware components.
Connections to Boundary Scan modules and to the NI USB-8451 SPI/I2C
interface have been prepared, to that it is also possible to use further
technologies for the test of future products. If - despite of these
broad resources – additional functionality should be required, it is
possible to integrate any new technology time- and cost-efficiently,
because of the modular structure.
The main components of the standardized test stand for Miele are:
Miele’s existing CVI-based tester software has been expanded and adapted towards TestStand. NOFFZ has developed new Custom StepTypes, such as Custom Step Type NI DC 4110 (DC Power Supply).
Step Type NI DC 4110 is not only able to configure all functions of 4110 but also to generate comments automatically. Simple configuration of all channels and direct adjustment of current and voltage values allow for a fast work flow during project realization.
Conclusion and future prospects
Based on the introduced concept, new tester systems could be assembled and supported. Employees can be trained quickly with the new tester system, because it is a standard tester offering a defined framework and a high degree of reusability.
In the future, further optimizations of this test stand will be implemented, including database-support, hardware and project abstraction.
The main components of the standardized test stand for Miele are:
- IPC including PXI
- 19“ chassis including customized signal conditioning for 240V
- Pressure controller
- Switching matrix, incl. device adaptor
- Rollaway measurement system, incl. pneumatic and main switching unit
Miele’s existing CVI-based tester software has been expanded and adapted towards TestStand. NOFFZ has developed new Custom StepTypes, such as Custom Step Type NI DC 4110 (DC Power Supply).
Step Type NI DC 4110 is not only able to configure all functions of 4110 but also to generate comments automatically. Simple configuration of all channels and direct adjustment of current and voltage values allow for a fast work flow during project realization.
Conclusion and future prospects
Based on the introduced concept, new tester systems could be assembled and supported. Employees can be trained quickly with the new tester system, because it is a standard tester offering a defined framework and a high degree of reusability.
In the future, further optimizations of this test stand will be implemented, including database-support, hardware and project abstraction.