Astro Digital - Vibration Testing

Small satellites, more commonly known as CubeSats, have gained popularity because of their miniature size and their data acquisition techniques. These satellites are being launched at a record pace and have roped big players into this aerospace segment. Astro Digital is a company that risen to the challenge of land mapping and hazard detection using CubeSats.

Astro Digital has been creating APIs and CubeSats for geological mapping, natural disaster management, forest management, water cover sensing, etc. Sentek Dynamics is proud to have a hand in their projects.

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Astro Digital used the Sentek Dynamics’ vibration testing system at the Sentek Dynamics’ facility in Santa Clara, CA to test the Landmapper-BC. Astro Digital made use of Sentek Dynamics M-Series shaker and Crystal Instruments’ Spider-81 controller for sine-sweep and random vibration tests. The DUT was tested in the vertical and horizontal positions.

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The M-Series shaker has an active armature suspension system, load support, and a guidance system to ensure quality test setups. The usable vibration control frequency range for the M-Series shaker is from 5 to 3000Hz. Some shaker systems do come with a long stroke option, thereby giving our customers the best testing conditions possible.

The Spider-81 controller used for the test is equipped with the patented dual ADC and provides superb dynamic range of 150 dB; thus guaranteeing a high accuracy in control. The controller many safety features implemented to protect the device under test. Multi-tab and multi-screen support is provided to allow viewing of multiple signals simultaneously. The random vibration controller provides precise multi-channel control in real time. The device under test is subjected to true random noise with a precisely shaped spectrum with either Gaussian or non-Gaussian amplitude statistics. With a control dynamic range up to 90 dB, up to 512 channels can be enabled for control, notching, monitoring and time data recording. The recording option records time-stream data at the full sample rate on all input channels. A unique hardware/firmware/software design featuring spectral overlapping provides a fast loop time of less than 15 ms in a typical test.

Astro Digitals’ Landsat and Centinel are enhancing our geographical monitoring capabilities with their state-of-the-art technology. We at Sentek Dynamics and Crystal Instruments will continue to support such efforts by providing proven, high quality testing to improve product reliability and enhance technology.

The Automotive Testing Expo 2017 - Novi, Michigan

The 2017 Automotive Testing Expo provided a full display of Sentek Dynamics’ latest environmental testing capabilities. Not only was a simultaneous 3-axis vibration test system on display, it was paired with a Crystal Instruments Spider-81 multi-axis capable vibration controller as well.

In addition, the recently released temperature, humidity, and vibration environmental testing line boasted a clean, cutting edge chamber design to pair with Sentek Dynamics’ industry leading air and water-cooled electrodynamic shakers. When paired with the Spider-100, the Sentek Dynamics solution offers independent control of temperature, humidity, and 3-axis vibration control all from a single control PC, which makes the offering unique to the market.

Whatever the automotive environmental testing needs, look no further than Sentek Dynamics and Crystal Instruments for your one stop, turn-key solutions provider.

Announcing Sentek Dynamics Russia


Sentek Dynamics is pleased to announce the opening (effective July 2017) of its first Russian office. Located in the city of St. Petersburg, Russia, Sentek Dynamics chose this site due to its unique combination of both culture heritage and industrialized technology subdivisions.

Russian Sales Manager Oleg Turkalov worked in conjunction with Sentek Dyanmics' headquarters in California to establish the location. The intent of the Russian office, Oleg notes, is to “focus on better serving our Russian customers.”

Sentek Dynamics' management believes that a brick and mortar establishment will lay the foundation for quick and localized support. In this on-demand economy, Sentek Dynamics views decreased turnaround times as an essential factor to staying competitive. This includes a variety of support functions, including the assistance of local resellers and customer training.

Russia’s increased activity in its technology industry is welcomed by companies like Sentek Dynamics. Over the past 5 years, Sentek Dynamics has worked hard to serve Russia’s testing needs through a variety of data acquisition and vibration control products.

With the opening of this new location, Sentek Dynamics will now be able to interact with customers on local time. Sentek Dynamics hopes this will increase its favor among customers with the goal of being the preferred solution provider for vibration control and data acquisition needs.

For more information, visit our website or contact us.


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Sentek Dynamics' supplies vibration test equipment and environmental test chambers to simulate "real-world" environmental conditions for a wide-variety of aerospace, automotive, electronics, medical, appliance and independent test lab applications.

The European Automotive Testing Expo 2017

This past month (June 20th, 21st, and 22nd) Sentek Dynamics along with controller company Crystal Instruments attended the European Automotive Testing Expo in Stuttgart Germany.  Over 6,000 attendees came out to visit more than 300 exhibitors. There was a wide variety of testing equipment displayed at each of the exhibits; it ranged from virtual-reality driving simulators to test and measurement devices including temperature chambers, shakers, and vibration controllers.  Sentek Dynamics and CI together showcased the largest of their L-Series shakers along with a Spider-81 Vibration Controller.

This year’s prominent theme was the focus vendors paid towards testing the limitations of autonomous driving instrumentation.  As autonomous vehicle technology continues to develop, automotive manufacturers need to employ carefully thought out tests to ensure the reliability of the software that drives each vehicle, as well as the computers and sensing elements that provide the necessary feedback to allow the software to navigate the car down the road.

Developers of driver assisted and driverless instrumentation have many situations for which they need their hardware to perform perfectly under.  One such situation that has become evident to CI and Sentek is the increased requirement for vibration and shock testing to test the sensing elements used in autonomous vehicles including lidar, video cameras, radio cameras, and GPS computers.  CI and Sentek witnessed this trend first hand and are working closely with autonomous vehicle designers to provide the best vibration testing equipment to test autonomous driving instrumentation.

This year's European Automotive Testing Expo gave both CI and Sentek the perfect platform for which to discuss and share their knowledge of vibration and specifically how it relates to autonomous driving equipment.  Interested folks stopped by the booth and many engineers walked away with a new understanding on how Sentek Dynamics and CI have assisted in vibration testing in the past and how they can provide their knowledge in the future.

To learn more about the mechanics of vibration and vibration-testing autonomous vehicle equipment and other developments from Sentek Dynamics, please send us an email (, follow our blog updates (, or come see us again at the upcoming Automotive Testing Expo in Novi Michigan, USA.

Commissioning Sentek Dynamics’ THV Series AGREE Chamber

Recently, the Sentek Dynamics Team commissioned a Sentek Dynamics THV Series AGREE Chamber* at a major US aerospace company.  An identical chamber is scheduled to be commissioned at the company’s Canadian facility in August 2017.  

*Sentek Dynamics THV Series environmental test systems offers a turn-key solution for product development and reliability improvement.  The THV Series chambers combine temperature, humidity, and vibration testing into one whole chamber.  This method of testing, also known as The Department of Defense’s AGREE (Advisor Group on Reliability of Electronics Equipment), subjects the device under test (DUT) to a variety of simultaneous temperature, humidity, and vibration conditions that can be applied to a wide-range of military and commercial test requirements.
THV Series environmental test systems uses the Crystal Instruments’ Spider-100 controller which integrates the industry recognized Crystal Instruments EDM software for vibration control for precise control of temperature, humidity and vibration across the test regime.  Chambers are offered in several sizes with shakers ranging from 22 kN (4840 lbf) to 391 kN (88,000 lbf).

Developing an efficient installation and commissioning process requires an understanding of facility requirements for electrical power, water, compressed air and laboratory layout.  The Sentek Dynamics team excels at working closely with customer personnel to develop a coordinated plan.  Status updates are communicated through weekly meetings and the include the discussion of:

  • Identifying of pre and post-installation activities
  • Documenting discussions with customer staff regarding facility requirements
  • Coordinating of sub-contractors, for rigging, city permits, and electricity, water and compressed air hookup
  • Shipping and receiving logistics, off-loading, unpacking, and positioning system components at their final locations.
  • System start-up and final acceptance                     

The successful commissioning of the chamber is confirmation that the Sentek Dynamics team understands the customer’s needs. Specifically, the necessary planning to accomplish the installation and commissioning of the system in an efficient manner.

System delivery

System delivery

System installed and commissioned

System installed and commissioned

PID Control Parameters of the THV (Temperature, Humidity and Vibration) System

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The key to the superior performance of the THV Series environmental test systems is the powerful yet practical Spider-100 controller. The Spider-100 controller supports Crystal Instruments’ versatile Environment Data Management (EDM), vibration control software (VCS), and dynamic signal analyzer (DSA) software.

The Spider-100 is specially developed for combined temperature, humidity and vibration testing where the device under test (DUT) is subjected to simultaneous temperature cycling, variable humidity, and vibration. The unique capability of simultaneous control for combined testing is made possible by the excellent control design which allows for control of a shaker, refrigeration units, electric heating elements and humidification components.

The algorithm of the temperature and humidity control is based on PID control theory. It includes a very smart, self-tuning capability that allows the software to obtain the optimum PID parameters using several iterations of self-tests. This blog briefly describes the software setting of PID control and the self-tuning capability.

PID Control Parameters and Self-tuning
PID control parameters can be based on temperature/humidity ranges or temperature ramp rates and can be configured in the self-tuning section. Due to the non-linearity of the control system, P, I, and D parameters have different optimal values in different ranges. Please use the PID self-tuning function to ensure optimum values in different test regimes. Currently, the self-tuning region is automatically calculated based on the run schedule.  If the temperature/humidity parameters in a certain range need to be tuned, the self-tuning feature inside the self-tuning region can be turned on.

Click the Manual Edit Value link as shown below to edit temperature and humidity value ranges then configure the PID parameters which affect the control characteristics directly. Because the control system is non-linear, the optimal values of P, I, and D parameters are most likely not the same. The values can be optimized via PID self-tuning. The self-tuning region has various colors to represent the status of each range block. If the block color is light yellow it indicates heating, cooling, humidifying, and dehumidifying is not complete. If the block color is bright yellow, it indicates at least one action of heating, cooling, humidifying, or dehumidifying is complete. If the block color is green, it indicates all heating, cooling, humidifying, and dehumidifying actions are complete.

Click the PID Self-tuning button to open the self-tuning page where there are 5 options.

  • All Self-tuning
  • Heat Self-tuning
  • Cool Self-tuning
  • Humidification Self-tuning
  • De-humidification Self-tuning

P, I, D parameters can also be manually set. Click any region inside of Self-tuning region, the PID parameters corresponding to that region will show below it. Click Manually edit the value, the P, I, D values of the current region can then be modified. Hover the mouse over How to set P, I and D and a detailed explanation about P, I, and D parameters and their suggested regions will be displayed.

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Click Reset all to return all PID parameters in all regions to the manufacturer’s default settings. Click Show all values to see a detailed list of PID settings showing the PID parameters in each region. Altogether there are 18 cells consisting of one 9-cell region based on values, and one 9-cell region based on ramp rates.  Each cell has 4 groups of PID parameters covering heating, cooling, humidification, and dehumidification for a total of 72 groups of PID parameters.

The self-tuned PID parameters can be saved so that they can be loaded from the library in other tests with the same temperature/humidity profile, without another self-tuning.

If the control is not optimized during testing, the PID parameters can be modified during the control process. After the modification click Apply all to save the updated parameters in the library, and the updated parameters will take effect immediately.

The PID parameter settings contain information about the PID control algorithm and specific PID input settings. Input temperature and humidity values or input humidity values with temperature ramp rates are used as part of the PID control algorithm. These settings are configured during factory acceptance testing of the system and are not recommended to be adjusted without assistance and or approval from Crystal Instruments. For advanced operations, PID parameters can be exported to a local drive and imported from previously saved settings if adjustments are needed for control optimization.

The PID control settings involve adjustments to the control interval durations and selection of various cooling methods (compressor, liquid nitrogen and liquid nitrogen with compressor).

The Control interval specifies the duration of time the compressor, heater or humidifier will turn on to control the temperature and/or humidity of the system.

The Range of temperature control initiates refrigeration when the temperature lowers to the target value specified.

The Nitrogen control interval is only relevant when choosing the “liquid nitrogen” or “liquid nitrogen and compressor” option for the cooling method.

The Compressor control interval controls the duration the compressor is turned on for cooling and dehumidification control.

The Heat dead band and Cool dead band specify the temperature range outside of which the “I” (Integral) control will not be activated. Once the specified temperature is surpassed, only “P” (Proportional) and “D” (Derivative) control are active.

The Temperature AVG (average) and the Current channel AVG (average) are the average number of temperature and current channel readings used for control, respectively.

The Self-tune function is used when automatic calculation of the specific PID settings is desired.

The Big temperature rate limit is an option valid only when the cooling method is set as “liquid nitrogen and compressor”. If the temperature changes at a rate less than this specified value, the compressor will be used for cooling. Otherwise, Nitrogen will be used for cooling.

The Humidify dead band and Dehumidify dead band specify the humidity range outside of which the “I” (Integral) control will not be activated. Once the specified humidity is surpassed, only “P” (Proportional) and “D” (Derivative) control are active.

Reference channel control is applied when the temperature difference from the sensor on the UUT to the chamber temperature is known. This known temperature difference assists in overall temperature control.

Need to run ASTM transportation tests? Look to Sentek Dynamics to handle your vibration test needs.

ASTM transportation tests (such as ASTM D4169) are commonly used to simulate vibrations induced by the shipping of containers via truck, air, and rail. Often times these tests require very low level random vibration profiles which can be hard to run and control. On top of that, many of the profiles begin as low as 1 Hz, which can cause problems as well.

For these reasons, selecting the appropriate equipment can be tricky. A Sentek Dynamics shaker with the proper isolation options can reduce the resonance of a system at low levels, and when combined with a Crystal Instruments Spider controller and a PCB high sensitivity accelerometer (for example: model number J353B34) the system will excel when running the required profiles. Look no further if you are in search of the best equipment for the job!