Do you encounter high deviations of contactless analog results for EMV testing with your current setup? Does it take ages to compare the delta between your in-house test results and those from the certification laboratory? 3 tips to get stable RF analog test results.

1.    Temperature and humidity - control the environment

Sounds like a no-brainer, but stable environmental conditions are a key factor. Thus, if you make sure to test at identical temperature and humidity, the more stable will be the test results - and less repetitions will be needed. The allowed laboratory range of 23 ± 3 degrees Celsius for the ambient temperature does not fully align with the allowed uncertainty of electrical measurements for VS,OV. This is the power emitted by the EMV®-TEST PCD. Therefore, it does matter if you increase the temperature, even within this range. The EMV-Test PCD is highly sensitive to humidity changes. Thus, the quote "never drink coffee next to an EMV-TEST PCD" by a lab manager holds true.

2.    Setup procedures - impact on verdicts

The results of the setup procedures directly impact the approval verdicts. These procedures compensate for minimal hardware deviations of the EMV test equipment. Hence, the results are taken as reference values and factors for calculation of acceptance criteria. For example, in PICC Analog 3.0  the test case CAB 111 voltage drop is calculated with EMV-TEST PICC 2 value as reference. In PCD Analog 3.0 for minimal, nominal and maximal load modulation testing all three EMV-TEST PICCs are measured for reference.
In addition, setup values can become inconsistent, if heating effects of mandatory components used in the reference antennas are not considered. Thus, load modulation setup procedures shall implement a waiting time to avoid those effects.

3.    Positioning - mechanical accuracy is king

EMVCo requires perfectly parallel orientation of payment and acceptance devices. For analog testing, automation with a robot is mandatory. Important to know: Vertical accuracy, in EMVCo terms the "z" parameter, has the biggest impact on electrical measurements. Therefore, the more precise the teach-in with the robot is, the better the repeatability of test case results will be.

What makes a robot teach-in procedure more precise?

1.    The excellent repeatability of the robot.
The robot does not only allow the tiniest step sizes, but it also returns exactly to the position defined in the teach-in of your device. Repeatability is a common parameter to be found in each robot fact sheet.
2.    The teach-in concept
A comprehensive teach-in concept shall consider all mechanical and human factors. The teach-in concept allocates all relevant accuracy factors in the overall budget of allowed tolerances. As many different test operators are involved, variations in accuracy are imported, because human behavior differs. Here, excellent usability like camera-assisted teach-in steps help to minimize this kind of deviations. However, the biggest impact on accuracy is to minimize the budgeted tolerance used up by mechanical components. For example, the Perspex plate of the EMV-TEST PCD or the holder for the EMV-TEST PICC need a highly accurate manufacturing process.
3.    Well-trained test operators
Although a robot automates positioning, it does not replace careful test approval management by the test operators. They make sure that the components work under their optimal conditions regarding temperature and humidity. They also check consistency of ICS data from the product provider, manage the device in the correct test modes, and charge devices sufficiently before starting the approval. The simpler to operate the test tool and the robot, the more focus remains for the approval itself.
 
Temperature and humidity control, well-executed setup procedures, and, most important, highly accurate robot positioning hugely pay off for RF analog testing results making them: stable, reproducible, trackable. 
 
Fed up with unstable results? Let us help you to stabilize.

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• EMV
• EMVCo 3.0
• EMVCo Level 1 Tests
• EMVCo
• Contactless