A large refrigerator manufacturer interested in improving product reliability underwent a major upgrade of its engineering facility. The manufacturer’s goal was to replace a manual system with state-of-the-art equipment and thereby gather better product test data. This multi-phase upgrade project included the installation of a new environmental chamber at the facility with an integrated control and data acquisition system.

Application Summary
The outdated test system was slow, tedious, and error-prone. Data was manually gathered from thermocouples located in pre-defined areas throughout each appliance under test. Collected data was recorded on paper, then hand-entered into a spreadsheet for later analysis. This process was highly labor intensive. As such, the manufacturer found it prohibitive to test the large number of refrigerators for a valid data sample. Moreover, the system was prone to human error at every stage. For example, temperature values were sometimes incorrectly recorded from the thermocouples, and incorrect values were also sometimes entered into the spreadsheet for analysis.

The manufacturer hoped to achieve the following results: to save money by completing tests more quickly and accurately, and to monitor a larger number of products over a longer period of time, yielding more substantial data samples.

IOtech’s Solution
The appliance manufacturer had a new environmental chamber, replete with instrumentation installed at its facility. This new chamber is able to control the test room environment, monitor and control test-refrigerator power, and collect key parameters from the refrigerator under test.

The new test system is equipped to collect data from up to 10 refrigerators, each fitted with 12 thermocouples and 3 sensors for capturing line voltage, current, wattage, and special events such as the opening and closing of the refrigerator door and the operation or non-operation of the fan. Every 30 seconds the system samples data points, stamps date and time, and logs data to the hard disk for later review. Because the system is operated remotely, it is equipped with a modem to download data or to upload changes in the control software.

The Integrated Solution
The new test chamber employs IOtech’s TempScan to collect thermocouple and sensor data. The TempScan was chosen because it offers:

• Up to 992 expansion channels with a very low cost-per-point
• Trigger output, permitting synchronization of the test chamber’s event recorder with the start of each scan
• Insertable temperature (TempTC/32) and voltage (TempV/32) cards that reduce overall system cost and complexity by integrating temperature, voltage, current, and wattage collection into one instrument
• An efficient, low-profile rack-mount design
• Automatic date and time stamping that eases software programming

In addition, the TempScan can read all 150 of the application’s channels involved up to six times per second, with each reading being derived from the average of 16 samples taken in even intervals over one AC line cycle. This technique eliminates the 60-cycle noise that plagues thermocouple measurements.

Conclusion
The TempScan offers a cost-effective means of measuring a large number of thermocouple or voltage inputs. Its design makes it easy to use as a stand-alone instrument or to incorporate as a component of a larger system.

See complete application information in PDF format.