How to implement accurate and cost effective mobile data recording
Testing new products is a time-consuming and expensive task. Yet it has to be undertaken since it underpins the ability of manufacturers to develop new products capable of meeting market demands. Often field testing is needed in addition to any bench testing that may be required.
Increasingly, one of the key requirements of any DAQ equipment is its ability to successfully capture and record all relevant data. This is necessary because analysis can then be undertaken separately and enables different engineers to remotely access test data on particularly complex projects. Reliable data recording also ensures that valuable engineering time is reduced while taking any actual measurements.
Surveys, such as the one conducted by HBM in 2010, show that a number of key factors need to be considered when selecting DAQ recorders. One important consideration is where the measurements are taking place since equipment being used for mobile use needs to be very robust; nearly 40% of applications are outdoors or in vehicles where ambient conditions are highly variable. Some 20% of DAQ tests are conducted in ambient temperatures of greater than 60oC while around 10% are in temperatures of less than -20oC.
Another important consideration, especially for mobile applications is the equipment’s capacity to utilize different power sources such as an on-board vehicle network, DC voltage, or a separate battery supply.
Finally the functionality of the DAQ recorder needs to be considered in terms of the types of measurements, the level of channel count needed and its ease of use. DAQ recorders should have multi-functional capabilities to capture and record different measurement quantities. Consideration should also be given to integrating the recorder into centralized and/or distributed systems.
Some 20% of all measurements utilize between 32 and 64 channels while a further 20% of applications need more than 64 channels. Any DAQ recorder needs to be capable of capturing these higher channel counts but this should not be at the cost of accuracy. Accuracies of up to 0.1% of the measured value are needed in 40% of applications while some 20% demand accuracies of 0.05% of the measured value.
Above all any DAQ recorder must be capable of operating continuously in a wide range of field conditions while securely and reliably recording data.
HBM has recently launched its CX22W to provide simplified and highly flexible mobile data acquisition during field-tests. The multi-functional CX22W data recorder extends HBM’s well-established QuantumX series.
The CX22W data recorder uses an integrated Windows Embedded operating system to give users the stability and familiarity of Windows technology. This means that the CX22W data recorder processes measurement data directly; it does not need connection to a PC.
The CX22W is a compact unit identical in size to all other modules in the series. The QuantumX data acquisition system provides users with a flexible collection of mechanical, electrical and thermal measuring devices in a modular format.
This gives users a highly scalable system that can capture a wide range of data by connecting with other modules for any application. The scalability and ease of use of the CX22W data recorder makes it highly suited to mobile tests such as automotive tests.
These aspects also make the CX22W highly suited to long-term static measurements. In stationary field-tests the data recorder fully independently acquires measurements, over long periods of time, from distributed measurement modules. This feature is particularly useful for the monitoring of fixed structures such as wind power plants, bridges, buildings or other industrial facilities.
The CX22W can perform autonomous data acquisition, processing, recording and storage as well as optional visualization. The recorder acquires measurement data completely autonomously and stores it locally on a robust, removable CF card. Data can also either be retrieved via Ethernet or wireless LAN.
The CX22W’s flexibility means that numerous additional functions, such as smart trigger or calculation of virtual channels, are readily available. It can be freely configured and individual graphical user interfaces for connected touch screens can be created easily. Any set parameters can be saved for individual projects and restored at any time when needed.
By contrast HBM has developed the SoMat eDAQ specifically as a sealed stand-alone DAQ and recording system to meet the demand for testing in extreme and highly variable environments. The SoMat eDAQ has been engineered to be rugged and mobile and is swept sine tested to 20Gs to ensure data integrity regardless of the ambient conditions and external factors such as high levels of variable vibration. The SoMat eDAQ is a sealed system; there are no cooling fans, filters, open cards or drives.
The SoMat eDAQ is made of proprietary designed layers and utilizes components specified to ensure it can deliver mobile data acquisition regardless of the operational conditions. The SoMat eDAQ does not operate on Windows; it has a custom Linux OS and an indestructible file format.
To enhance its recording capabilities, the unit features SoMat DataModes™ that allow users to save data in multiple, easy-to-manage and analyze formats such as Burst History, Time-at-Level, Event Slice, Peak/Valley and Rainflow Histograms.
The system can accept a wide range of input powers from 10-60V DC and is fitted with internal back-up batteries to protect it from unplanned power losses or low voltage occurrences. The unit has been designed with leading-edge signal conditioning and has the capacity for a wide scope of on-board data processing. Various triggering options make sure you not only get your data in the format you want, but also when you want it.
The eDAQ utilizes Ethernet and hosts its own web server with a configurable IP to provide simplified communication through wireless WWAN modems giving global access to the data. Additionally the SoMat eDAQ can be integrated with GPS receivers and synchronized with GPS timing signals. These features allow multiple SoMat eDAQs to be wirelessly synchronized so that virtually limitless channel counts can be accommodated.
A key requirement of any DAQ recorder is the ability to successfully capture and record all relevant data regardless of the operational conditions. Careful consideration of the actual test requirements is important and it is best to select equipment that offers engineers a system that is easy to set up and operate while ensuring data integrity.