Customer Solutions

Siemens Actuator Test System Gains Flexibility and Compatibility with LabVIEW

Author(s):

Thomas Niederberger, Siemens; Karl Suter, Siemens

Industry:

ATE/Instrumentation

Product:

Data Acquisition, GPIB & Instrument Control, LabVIEW, NI TestStand, Signal Conditioning

The Challenge:

Developing a test station for mechanical actuators with test parameters that work with an ACCESS database via a LAN connection.

The Solution:

Building a compact test station using LabVIEW and Test Executive software combined with National Instruments hardware installed in an industry-standard PC to build a compact test station.

Introduction
At Siemens Landis & Staefa Division, we need to perform tests on mechanical actuators, measuring anywhere from 30 to 50 parameters on each. The tolerances are stored in a database which helps us maintain a large number of different part numbers.

Until now, our test software did not run on the Windows platform and therefore was not compatible with the rest of our office. In addition, we wanted the ability to analyze the data on our PC. The flexibility of National Instruments LabVIEW helped us develop this system. Currently, we are using four of these testers worldwide -- one in Switzerland, two in Chicago, and one in Korea. The different tests in the system include measurement for torque, as well as field tolerances and settling parameters. Each test takes anywhere from 50 to 70 seconds to perform. A bar code placed on each actuator tells the test station which tests to carry out on the actuators.

A PC-Based Approach
We selected a PC-based approach to give us greater flexibility in carrying out our various system tests. With a PC-based approach, we gain more compatibility with systems already running in our office.
LabVIEW not only helps us gather information, it helps us view it better. The Test Executive software, meanwhile, provides a variety of modular tests that make it easier to get things done. The ready-to-run GPIB and DAQ hardware give us more flexibility, compatibility, and overall possibilities.

System Setup
The hardware, including signal conditioning boards is in a robust electrical rack in a mechanical housing. We have diverse hardware cards in our industrial PC. Within this test system, we test around 50 different parameter types, which is why a database works best. We store the test parameters in an ACCESS databank using various formulas. We then use an SQL Toolkit for reading the databank.
We use an array as the central part of the whole test. The first part of the array is filled with data coming from the database; the second part is filled out by results coming back from the test steps. The array is then used for saving SPC data and printing.

The Software
The program has three windows -- the Test Executive, a window that displays the test results, and a window that displays the torque and position of the actuator. The test results and dates for the graphs help determine the data structure. Information taken from sampling the turning movements and their position is stored in a separate thread. Through this, we can view the same hardware parts from the various programs. We use several virtual instruments (VIs) to help determine this. Along with an automatic test station with a comfortable interface for the operator, we wanted to control the station manually for engineering purposes. Thus, we implemented two VIs, one for controlling all the I/Os and one for graphically switching the matrix.
In case of unit under test (UUT) failure, we print repair instructions to help the operator. These instructions are stored in the ACCESS database.

An Efficient Solution
Using a PC-based approach, we save time in system development because it is easier to develop and debug new tests. We plan to use similar solutions on additional Siemens products in the future.

For more information, contact:

Thomas Niederberger

E-mail: niederbt@ch.sibt.com; or

Karl Suter

E-mail: suterk@ch.sibt.com

361676a01.pdf

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