Radiation Measurement Test System for Cellular Phones

Author(s):
Angel Olivares Camps - Samsung Electronics

Industry:
Consumer Goods

Products:
Data Acquisition, Digital I/O, High-Speed Digital I/O, TestStand, LabVIEW, Instrument Connectivity

The Challenge:
Automating three processes that had been done manually by three workers into a unique automatice process that executes sequentially all three in one, reducing the need for one worker.

The Solution:
Using programs developed in NI LabVIEW graphical programming environment with NI TestStand test executive to control with GPIB and an input/output digital multicard.

Introduction
The necessities of reducing costs and increasing the speed and the quality of the manufacturing process required the implementation of this automatic system. We developed this system in compliance with all the guidelines from our headquarters in Kumi, South Korea and tailored them to meet our need of producing a high quantity of cellular phones with minimum staff.

System Implantation
In a manufacturing process of cellular phones, some tests with radio frequency equipment (RFE) are required such as - adjustment of internal parameters of the phone, radiation tests, and final test. All those processes involve a software control, which is developed in our headquarters in Kumi, South Korea, except for the radiation tests that are done manually.

The manual process is as follows- the worker puts a set on a special jig that has an antenna coupler, makes a call to the RFE and checks visually some measurement parameters while changing others. If the parameters that the worker is checking are within the specified limits of the work instruction, the set will be considered right, otherwise the test is repeated. If the test fails for the second time, the cellular will be rejected. This working method takes too much time with the risk that any visual test can be unreliable (the level of concentration of a person realizing the same operation during 8 hours is not consistent at all).

This is why we developed an automatic program that remotely controls this process through GPIB - an HP8922 measurement device (GSM/DCS base station). This makes some GSM measures, enabling the worker to simply pulse "ENTER" on a mini-keyboard and complete the test. This is completed with an average time reduction of about three seconds and a 100 percent increase in reliability. Some time later, the storage of all the measures in an excel file was introduced. With this capability we can extract values and make a statistic analysis to determine whether the measures are stable and the RFE are well calibrated.

Dual-Band Model
Once a dual-band model was launched, due to process specifications two more workers were added to the production line to execute two new tests - the HANDOVER test (change from GSM to DCS) and the DCS Radiation Test. First, the old program was modified to adapt to the Handover and DCS tests. After balancing some line positions, we integrated the GSM Test with the new ones (figure 1). With this integration, we avoided $900,000 of increased employee operation costs per year.

To provide for greater efficiency in a competitive wireless industry, we developed a test environment where one PC controls up to four pieces of equipment simultaneously.
This system, paired with the RFE and production line speed, increased productivity and avoided bottlenecks in production line.

To develop this new application, we chose TestStand - a software platform that allows us to use all the code previously developed in LabVIEW and the ability to easily modify our sequences. To make the process easier for the worker we put two seven-segments on each jig. With a digital input/output multicard we activated outputs that codify error values in our seven-segments.We chose a High-Speed Digital I/O Card (DAQCard-6533), which has four ports of 8 bits each. With each port, we control two seven-segments due to a printed circuit board that decodes four bits into seven outputs for the display (figure 2). Through this process, 32 bits arrive from the PCMCIA, and we manage 8 displays. All the possible errors of the test are coded by the displays with a specific code. For example, if the set is acceptable, we codify it with "00". When the test has finished, there is a beep and the numbers in the displays start blinking. This lets the operator know when a new set can be put into the jig to start a new test.

Introduction
The necessities of reducing costs and increasing the speed and the quality of the manufacturing process required the implementation of this automatic system. We developed this system in compliance with all the guidelines from our headquarters in Kumi, South Korea and tailored them to meet our need of producing a high quantity of cellular phones with minimum staff.

System Implantation
In a manufacturing process of cellular phones, some tests with radio frequency equipment (RFE) are required such as - adjustment of internal parameters of the phone, radiation tests, and final test. All those processes involve a software control, which is developed in our headquarters in Kumi, South Korea, except for the radiation tests that are done manually.

The manual process is as follows- the worker puts a set on a special jig that has an antenna coupler, makes a call to the RFE and checks visually some measurement parameters while changing others. If the parameters that the worker is checking are within the specified limits of the work instruction, the set will be considered right, otherwise the test is repeated. If the test fails for the second time, the cellular will be rejected. This working method takes too much time with the risk that any visual test can be unreliable (the level of concentration of a person realizing the same operation during 8 hours is not consistent at all).
This is why we developed an automatic program that remotely controls this process through GPIB - an HP8922 measurement device (GSM/DCS base station). This makes some GSM measures, enabling the worker to simply pulse "ENTER" on a mini-keyboard and complete the test. This is completed with an average time reduction of about three seconds and a 100 percent increase in reliability.
Some time later, the storage of all the measures in an excel file was introduced.
With this capability we can extract values and make a statistic analysis to determine whether the measures are stable and the RFE are well calibrated.

Dual-Band Model
Once a dual-band model was launched, due to process specifications two more workers were added to the production line to execute two new tests - the HANDOVER test (change from GSM to DCS) and the DCS Radiation Test.

First, the old program was modified to adapt to the Handover and DCS tests. After balancing some line positions, we integrated the GSM Test with the new ones. With this integration, we avoided $900,000 of increased employee operation costs per year. To provide for greater efficiency in a competitive wireless industry, we developed a test environment where one PC controls up to four pieces of equipment simultaneously. This system, paired with the RFE and production line speed, increased productivity and avoided bottlenecks in production line.

To develop this new application, we chose TestStand - a software platform that allows us to use all the code previously developed in LabVIEW and the ability to easily modify our sequences. To make the process easier for the worker we put two seven-segments on each jig. With a digital input/output multicard we activated outputs that codify error values in our seven-segments.

We chose a High-Speed Digital I/O Card (DAQCard-6533), which has four ports of 8 bits each. With each port, we control two seven-segments due to a printed circuit board that decodes four bits into seven outputs for the display. Through this process, 32 bits arrive from the PCMCIA, and we manage 8 displays. All the possible errors of the test are coded by the displays with a specific code. For example, if the set is acceptable, we codify it with "00". When the test has finished, there is a beep and the numbers in the displays start blinking. This lets the operator know when a new set can be put into the jig to start a new test.
This is a fully hierarchical system, from the Test Executive environment to the hardware and instruments.

Browse All Case Studies »