Custom measurement instruments, test fixtures and test automation

Do you need a measuring device or a product testing station?

In a special device that measures pressure, force, temperature, position, current or voltage, the range and conditions of use are the basic input. Production testing determines which defects will be caught and how a successful outcome will be defined. In automotive electronics ECU, supply, input/output, continuity and communications checks may be required for the auxiliary control module or wiring harness. If there is a documented CAN or LIN interface, the messages and expected reactions can be defined with the customer and included in the functional test.

Product variants, production quantity, number of operators and target cycle time affect the test architecture. With prototype verification, the production test to be applied to each product is planned separately. Limits for controls such as function, communication, supply current and sensor response are determined by the customer. The result is not just a pass/fail information; It is clearly recorded why it failed and which step to reexamine.

• Project-specific measuring device and data collection units
• Functional testing and end-of-line test stations
• Product variant, cycle time and defect scenarios

How do the sensor and analog front end affect target accuracy?

The sensor output may not be directly available to the microcontroller. For bridge type sensors, low-level voltage, current output or resistance measurement, the supply, amplifier, filter and converter structure are evaluated separately. The input range, actual noise performance, reference, settling time and channel switching are as important as the number of bits of ADC. The filtering and sampling approach is selected together with the required bandwidth.

The total error budget covers offset, gain, temperature drift, cables, connections and sensor effects. At low signal levels, PCB layout, shielding and supply noise can determine the outcome. Where isolation or input protection is needed, its influence on measurement performance is assessed. Zero input, known reference points and repeated measurements compare expected behaviour with actual prototype data; device accuracy is not declared from component data sheets alone.

• Sensor supply, signal conditioning and analog filter
• ADC, reference, noise and settling time selection
• Error budget extending from components to system level

Analog measurement chain, error budget and data acquisition board →

How does a mechanical testing fixture make the result repeatable?

Test fixtures are designed to locate the product correctly, make repeatable connections and provide an understandable operator procedure. Spring test pins, connectors, contact surfaces, clamping and product tolerances are assessed together. An automotive module may require an adapter, representative load and wiring harness connected to its product connector. Harness pin mapping and continuity checks form a different test flow. Incorrect placement and missing connections are detected by design; production functional testing is assessed separately from vehicle approval or product certification.

The fixture's own connection resistance, cable, and routing board are part of the measurement chain. In applications such as low resistance measurement, the connection method is designed separately. Mechanical wear, pin replacement, cleaning and maintenance access affect result stability throughout production. In projects involving electrical load, moving parts or operator access, protective structures and locking requirements are determined by risk assessment. Production safety conditions are included in the acceptance plan.

• Product-specific nest, connection and adapter design
• Contact repeatability, tolerances and maintenance access
• Incorporating fixture impact into the measurement and test plan

Recipe, serial number and result recording in end-of-line test automation

Test automation is a broader flow than sending commands to the device and reading the results. Product serial number, hardware and software revision, test recipe, station information and measured values ​​are recorded together. If there is a programming, identification or calibration step, its order and fallback behavior in case of error are determined. A rule is created to retest the failed product and preserve the previous results.

The operator interface clearly shows the next step, connection status and cause of failure. Administrator and operator permissions are separated to prevent uncontrolled changes to acceptance limits. The scope may include local logging, a server database or API integration with the customer's production software. We define whether testing continues during network loss, how serial-number conflicts are handled and how data is transferred later. Changes to test limits through software updates remain traceable.

• Serial number, recipe, revision and result association
• Sequence of programming, measurement and function testing
• Local recording, production software and API integration

How to demonstrate that the test system itself is working correctly?

For example, in the end-of-line test of a control board with sensors, known excitations are applied and measurement, communication and output responses are compared. In addition to sound examples, defined error examples also show that the test catches the defect. Passing a single example is not considered sufficient; Result variation for repeated placement, different operators and product variants is examined. The choice between test duration and measurement stability is made based on the data.

With the calibration target, measurement uncertainty and acceptance limits are considered together. The status of the references, ambient conditions and fixture impact are recorded; It is determined how the borderline products will be evaluated. A daily check sample, post-maintenance verification or periodic reference check can be planned. If an accredited calibration certificate is required, the relevant laboratory service is organized separately. Project testing does not imply accreditation or certification per se.

• Validation with known-good samples and samples with defined faults
• Examining operator, reinsertion and variant effects
• Plan for references, uncertainty and checks after maintenance

How are the test project's source files delivered to the production team?

We will sign NDA upon your request before technical sharing. Your product's circuit, error information, production limits and test methods are evaluated within the scope of the project. We do not offer customer designs in our own sales catalogue. Requirements, acceptance scenarios, and deliverables are listed at the beginning; prototype findings are translated into controlled revisions.

At the end of the project, the source code of the project, PCB design files, mechanical CAD models and technical documents are delivered. Test recipes, wiring diagrams, bill of materials, programming steps, maintenance information and result data structure are included in the delivery plan. Driver and license terms of third-party meters are displayed separately. Sample PCB production and electronic component assembly support is provided only for the prototype and verification process of customer projects developed by VOMRO.

• NDA and customer's project scope upon request
• Source codes, electronic and mechanical design files
• Testing, maintenance, recipe and integration documents