At ITM, we understand that our customers do not settle for good enough. When it comes to measuring and capturing data for real-world applications and structural analysis, you cannot compromise, so neither can we. Instead of having to pick and choose the most critical locations to measure, we ensure that you can capture every piece of data you need, simultaneously. Whether that is a single strain bridge, or thousands of strain channels, we make your data logging project a success.
On past projects, we have worked with our customers in the manufacturing industry to test the structures of their aerospace, mining, construction and other transportation equipment. Some of these applications not only needed to collect strain, vibration, voltage, and other signals simultaneously but also required well over a thousand total sensor channels. Network synchronization technology embedded within the NI cDAQ chassis allow users to account for the sheer number of channels during these structural tests. The true secret to our success in these high-channel jobs has been our iTestSystem software which leverages the cDAQ’s synchronization technology while providing an intuitive data acquisition and sensor configuration and setup.
iTestSystem is far more than just a barebones data collection software. It can be a time saver to our engineers by helping to sort channels, keep various tasks organized, and even provide an easy and quick way to view results with the integrated TestView Plus Application (shown below).
The mining shovel pictured below, which is similar to other equipment that ITM has instrumented in the past, illustrates a distributed data acquisition system for collecting data. Using iTestSystem, we can implement a modified tree synchronization topology to collect data from over 20+ cDAQ chassis simultaneously. Data can be collected in one giant file containing all sensor channels or saved into separate files based on location. In past projects, we saved over 1000 channels from strain, acceleration, and voltage sensors into a new file every 10 minutes. We added the sensor location to the sensor description, including the Boom, Operator Cab, Main Frame and Base. This allowed us to easily sort data both during and after the collection.
Our goal at Integrated Test & Measurement is to provide efficient testing solutions and services to address your company’s needs. If you need to measure high channel counts, or have questions about our rugged DAQ systems, software, rental equipment or testing services, then please contact ITM by phone or e-mail.
Contact Information: For more information on this Article, please visit iTestSystem.com or contact: Ryan Welker – Integrated Test & Measurement (ITM), LLC – email@example.com or (844) 837-8797
https://itestsystem.com/wp-content/uploads/2020/07/Rope-Shovel.png6281200Zach Ruckerhttps://itestsystem.com/wp-content/uploads/2020/05/itmlogo_Horizontal_3x1.pngZach Rucker2020-07-23 10:00:002021-10-07 19:37:00High Channel Count Structural DAQ Systems
If the COVID-19 pandemic has proven anything, it is that we live in a business climate where efficiency and accuracy have never been more important. In other words, none of us can afford to make costly mistakes.
With that in mind, I’d like to share some tips for you to consider when it comes to this important question: How Do You Estimate Test Engineering Services Costs?
For engineers, testing engineers and managers who find themselves estimating jobs, getting this step right will prove crucial not only to the success of your projects and bottom line, but also to the trust you build with your clients.
Define the project scope of work
The most important requirement is to properly define the project scope of work. This will not only help you determine the necessary hardware, software, and resources required, but it will also help you identify the customer’s expectations and project deliverables. Properly defining the scope of work will help eliminate or minimize overall project time, as it will prevent delays both during the preparation phase and testing phases. Defining the scope of work will require a deep-dive discussion with your client to fully understand their challenges and goals. Remember not to leave vague language in your proposals. In other words, be sure to define who is responsible to provide all that will be needed to fulfill the project. Without a clear definition of the requirements and deliverables, it leaves a lot open for misinterpretation and expectations.
Materials costs are key
With a properly defined scope, we next must determine what, if any, materials we need to procure. These include sensors, DAQ hardware and other installation supplies. Don’t forget to include the amount of time that will be required to prepare all the materials and hardware. Think through such things as what it will take to package the DAQ hardware for any special environmental requirements. Also, be sure to consider the time it will take you to set up the software configuration file and test all the hardware and sensors prior to deployment.
Onsite costs are relative
We also need to consider the onsite testing requirements and location specifics. Costs can mount quickly to cover general travel and living expenses, particularly when the job will take your team to remote places for extended periods of time. You need to think about daily commutes to and from the facility as well as the cost variance for different geographic locations. Flights, vehicles, hotels and meals are crucial to estimate as accurately as possible, and that’s going to take extra research on your part. Keep in mind that travel costs are NOT one-size-fits-all.
Build in the value of analysis
Some projects require analysis support and some do not. It all depends on the customers’ resources and requirements. We serve customers by providing raw data files and allow them to perform their own analysis, but we also have experience providing a complete turnkey solution including data analysis. This requirement obviously needs to be defined up front in order to accurately estimate the opportunity.
Hidden costs are crucial
You need to consider everything when estimating a project, and this commonly involves “access to the instrumentation areas” for our projects. We typically work on large, complex equipment that sometimes require additional tools and resources to access the sensor locations. This could include manlifts, scissor lifts, cranes, rope access and scaffolding. Since the equipment is quite large, you need to think about the amount of signal cable required and evaluate that against deploying a network of DAQ chassis which may be a cheaper solution than routing all sensors back to a single DAQ system. It will also be key to build in language and costs in your estimates to address unforeseen delays. For example, include factors that lie outside of your team’s control — resources not being available, no access to equipment, or even poorly performing equipment that will not allow your team to record good data.
All sensors and gauges are NOT created equally
Sensor installation can vary from a couple minutes to a couple hours depending on the application. The same is true of strain gauges. Depending on the testing environment, strain gauges can be installed quickly or become an arduous task. Some applications involve very high temperature and moisture concerns and may also need to survive for long periods of time, which may require a more robust epoxy that requires a heat cure before data can be recorded from the strain gauges. Some applications involve no environmental concern and are only needed for a very short duration. In these cases, the gauges can be installed quickly after surface prep using an industrial type fast curing epoxy. Similarly, some applications may benefit from using weldable gauges that can simply be tack welded to the specimen. This eliminates any challenges and reduces installation time by using special epoxies. These are typically much more expensive, so you must evaluate the economics of this option. In either case, the surface must be properly prepped (ground, sanded, polished) to the base material to ensure a good bond to the test piece.
Consider variable labor and expense rates
Our labor rates vary by skill level. Senior engineering and programming labor, for example, costs more per hour than our regular engineering and programming labor. Similarly, sending a senior technician will cost more per hour than a technician. Finally, as is common, materials and expenses are estimated at cost plus 10%. Labor Rates Link
Ryan Welker is a 25-year veteran in engineering, procurement and project management. Ryan currently serves as a Vice President of Operations at Integrated Test and Measurement (ITM) in Milford, Ohio. In this role, he oversees the daily operations and monitors all phases of project fulfillment, including customer inquiries, proposal development, scheduling and manpower, employee training, on-site installations, customer follow-up, and support.
Weldable strain gauges installed on a bulk material tank.
When it comes to measuring structural stresses and load, every application is unique, and sometimes that means using a different solution. In some cases where strain gauges are applied, it can be advantageous or even necessary to use weldable strain gauges instead of chemical bonding the strain gauges to the specimen.
Since many epoxies used to chemically bond strain gauges require specific heat and pressure for curing, it can be difficult or even impossible to use this method on large or irregular structures. Weldable strain gauges offer an advantage in this situation as they eliminate the need to clamp and cure any epoxies for bonding. In addition, weldable gauges can be installed in a variety of environments and weather conditions which offers additional advantages over traditionally bonded strain gauges. Although weldable strain gauges are applied differently, they function in much the same way as their bondable counterparts.
To properly install a weldable strain gauge, you will need:
Always remember to have the proper safety equipment on hand, such as eye protection and gloves, as well as any PPE required by your environment.
When installing a weldable strain gauge, you must first prep the area. Unlike bondable gauges, the area does not need to be polished to a fine degree. Simply degrease the gauge area, sand down any paint, coatings or excess debris and ensuring the area is purely metallic and free of chemicals is enough. A clean metal surface is important to the welding process.
After the part has been cleaned, you can position the gauge. Most weldable gauges come marked so you can align the grid properly. When the gauge is properly aligned, spot weld the gauge on either side of the gauge along the centerlines, to hold it firmly in position and prevent shifting as the gauge is welded further. Once secure, the gauge should be welded all around the carrier surface, as illustrated below.
Weldable strain gauge spot weld pattern.
Clean the area to be bonded (Remove all paints, coatings, residue and debris until the surface is smooth).
Mark center-lines for the gauge location with scribe and straight edge.
Place the gauge on the part, lining up the center-lines.
Spot weld the gauge on each line, to secure it in place.
Weld the entire perimeter of the gauge in the pattern shown above.
Installing strain gauges in the field for structural and fatigue measurements requires expertise and experience. Whether you use our iTestSystem software to stream and analyze strain signals for static measurements and real-world fatigue data acquisition or contract our software engineers to build a real time strain monitoring system, we will make sure you acquire quality strain data. Contact our strain lab and technicians to install strain gauges on test specimens or to design, build, calibrate, and test strain-based load cells.
Choosing an accelerometer for rotating machinery vibration measurements can be a daunting task since there are so many options available. This blog outlines the characteristics you should consider when choosing a piezoelectric single axis accelerometer for general purpose vibration measurements and presents some accelerometers to consider.
Characteristics of a General Purpose Accelerometer
When measuring vibration on rotating equipment such as motors, pumps, and generators, the most common measurement location(s) are on the shaft bearing housing(s) at the shaft centerline. At this location, typical vibration levels perpendicular to the shaft are < 100 g and the frequency range of interest is < 5000 Hz. A general purpose single axis piezoelectric accelerometer with either a 10 mV/g or 100 mV/g sensitivity fits this criteria.
Other characteristics to consider are size, mounting options, cable connections, grounding, and cost. Several mounting options are available. They include magnetic bases, adhesive bases and stud mounts. The mounting option you choose affects the frequency range of your accelerometer measurements. The table below shows typical frequency limits for accelerometer mounting methods.
Typical Frequency Limit
5 General Purpose Accelerometers
The table below shows some examples of stud mounted general purpose piezoelectric accelerometers. These accelerometers all have a female 10-32 coaxial / microdot connector. It is important to note that this is not a complete list of accelerometers and there are many options available from each manufacturer. I would encourage you to go to the websites linked in the table and see what’s available.
Last week our team successfully and safely installed another Boiler Monitoring System (BMS). This system, a Sootblower Fouling Detection (SFD) system, monitors structural and vibration sensors that quantify the boiler’s response to sootblower operations. The SFD system analyzes the boiler response data and outputs Key Performance Indicators (KPIs) such as fouling level, sootblower efficiency, and sootblower health to automated boiler cleaning systems.
This boiler uses over 50 sootblowers located at different elevations to clean soot build-up from boiler steam tubes. Since the vibration measurement locations are relatively far apart, the SFD system requires a distributed monitoring system consisting of several junction boxes that monitor and process data for groups of sensors. One team of engineers mounted the vibration sensors to the sootblowers and confirmed communication back to a local junction box containing the National Instruments condition monitoring hardware. The other team installed the junction box panels and terminated the sensor cables.
After all the sensor installations and terminations were completed, each sensor’s location and calibration were verified. While the sensor verification was being completed, one engineer worked with the mill IT department and the controls engineer to establish remote connection to the system and confirm communication with the mill’s automated cleaning system.
After commissioning the system and returning to our home base, our engineers are now monitoring the system through a VPN connection and assisting boiler operators with optimizing their cleaning process.
Over the years we have been tasked with identifying the root cause of machine structural failures. In many cases, we can determine the failure mode through strain and vibration testing, order analysis, modal analysis, and operating deflection shape analysis. What tests can you run when the damaging conditions are intermittent and not easily identified?
In these cases, we like to install a cellular networked temporary data acquisition (DAQ) system that can autonomously log vibration and strain data along with machine status data. We have deployed two types of DAQ systems to collect data remotely. An interactive system that includes an industrial PC running our iTestSystem software and National Instruments (NI) Compact DAQ hardware and a headless system that utilizes NI Compact RIO hardware. Our test engineers prefer using the interactive solution for troubleshooting because they can view real-time signal waveforms and collected data files, and then adjust the test parameters accordingly without having to reprogram the hardware.
Figure 1: Headless networked data acquisition system
When potentially damaging events are identified in the vibration and strain data collected by these systems, it is important to know the machine’s operating status. Collecting the machine status information is just as important as collecting the structural data. Many machines transmit these operating variables and operating stages over their network/bus. Recently we have recorded process data from Allen Bradley Control Logix PLCs via Ethernet/IP, mining machine data from a Siemens controller via proprietary TCP/IP protocol, boiler condition data from a DCS via Modbus TCP, machine pressures from PI historian via the UFL connector (TCP), and vehicle speeds and pressure via CAN. Fortunately, we were able to use and adapt LabVIEW communication protocol tools to build applications and addons that allow this network tag data to be collected along with structural data.
Figure 2: Modbus to Shared Variable Tool
After the data collection phase, our engineers perform statistical analysis on the sensor and status channels in all data files and aggregate the results into a database for searchability. To identify the root cause probabilities, you can process the channel statistics data using your favorite correlation algorithm or application. The image below shows an example data set containing related sensor data that was processed using a LabVIEW correlation test tool.
Figure 3: Correlation Test Example vi
Contact Information: For more information about our remote data acquisition service, our LabVIEW development service, or iTestSystem contact:
Image1: Shaft torque strain gauge installation example for field testing
Our engineers and technicians have epoxied, soldered and spot welded strain gauges for applications ranging from high temperature exhaust systems to miniature load cell measurements. Every application requires a unique understanding of the strain measurement requirements including installation environment.
If the strain gauge installation is to survive in the field you must plan for the conditions it will undergo. Three important variables that you should account for are temperature range, liquid exposure, and potential impact forces. These variables determine the type of strain gauge, epoxy, solder, wiring, coating, and impact/wear protection to use in the application. The table below shows which variables affect your installation choices.
Table1: Strain gauge installation variables
For more information about ITM’s strain gauging services contact Ryan Welker at email: firstname.lastname@example.org or phone: 1.844.837.8797 x702
https://itestsystem.com/wp-content/uploads/2019/09/Shaft-Torque1200x628.png6281200Ryan Welkerhttps://itestsystem.com/wp-content/uploads/2020/05/itmlogo_Horizontal_3x1.pngRyan Welker2019-09-13 18:01:532021-10-07 19:44:07Strain Gauge Installations for Field Testing
In order to prevent or troubleshoot structural vibration problems, it is important to characterize a structure’s dynamic behavior using both experimental and Finite Element Analysis (FEA) technologies. One method used to identify a structure’s vibration modes is to perform a roving accelerometer or roving hammer impact test. In an impact test, engineers measure the response of a structure from an impulse delivered by a calibrated hammer using tri-axial accelerometers.
Managing impact tests on large structures can be tedious and cost prohibitive, since they require collecting accelerometer responses at hundreds of locations to resolve the vibration motion. Not only do test engineers need to keep track of the locations, they also need to keep track of the orientation that an accelerometer is positioned.
Our test engineers have found that the most efficient and cost effective solution for collecting impact data is to use a National Instruments (NI) cDAQ chassis with either NI-9234, NI-9232, NI-9231 or NI-9230 IEPE modules along with a calibrated impulse hammer and between 3 – 9 tri-axial accelerometers. To collect, manage, and visualize the modal data, our LabVIEW software engineers developed the Impact Test DAQ, FRF Viewer, and 3D Animator applications for our iTestSystem software platform. These applications incorporate tools that our test engineers need to manage and validate the quality of their modal data while in the field.
For more information about impact tests, modal analysis, our iTestSystem Impact Test applications, or to schedule a modal test contact Mark Yeager or Ryan Welker.
When we develop LabVIEW™ applications for our customers, a common request is for a simple, resizable and intuitive user interface (UI) for data visualization. In these cases, we use a tree control and a subpanel. This type of UI functions like a tab control that automatically resizes. The main benefit of using a subpanel is to make your code more modular.
Figure 1: Modern User Interface with a Tree and Sub Panel.
To illustrate the modularity that this type of UI creates, I made an example LabVIEW™ project. The main VI shown above uses a tree control to switch between a VI containing a graph and a VI containing a table. I used our multi-queue event architecture for VI information communication messaging. The image below shows the main VI’s significant functions.
Figure 2: Main VI’s Block Diagram – Significant Functions
The main VI’s functions are listed below.
Initialize queues and events and then generate initialize event.
Initialize tree and add tree items.
When a user selects an item in the tree, generate data and then send it to the subpanel VI.
Receive SubPanel Ready event from a subpanel VI and then insert the VI into the subpanel.
Destroy queues and unregister for events.
In this example the subpanel VIs are very simple. They populate an indicator (table or graph) and then generate a SubPanel Ready Event. The two (2) subpanel VIs and block diagrams are shown below.
Figure 3: SubPanel VIs: Graph.vi and Table.vi
Contact Information: For more information on this example or our LabVIEW development service contact:
https://itestsystem.com/wp-content/uploads/2019/03/LabVIEWUI2.png6281200Mark Yeagerhttps://itestsystem.com/wp-content/uploads/2020/05/itmlogo_Horizontal_3x1.pngMark Yeager2019-03-07 02:11:282021-10-07 19:46:00Building a Modern User Interface in LabVIEW
ITM | Integrated Test + Measurement 227 Water Street, Suite 300 Milford, OH 45150
ITM provides software development, structural and mechanical testing services, industrial monitoring, strain gauging, and data analysis solutions to clients on six continents. ITM is a recognized National Instruments Gold Alliance Partner.