MadgeTech Shock101 Application Note

Application Note

Complete Environmental Monitoring

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UltraShock

What Does the UltraShock Do?

The UltraShock is a portable data logger designed to record the following environmental
variables: shock (g-force; impact/acceleration), temperature, humidity, and pressure. Recording
shock using the Shock101* data recorder is often adequate in many cases such as shipment
monitoring, or laboratory/drop testing. However, recording temperature, humidity, and
pressure, gives the UltraShock added versatility. In addition, these data loggers record the
vector sum, giving the user the overall acceleration data of the goods being monitored.

Using a built-in semiconductor (MEMS) accelerometer, various models of the UltraShock and
Shock data recorders can sense accelerations with ranges of ±5g, ±50g, and ±100g. This type
of sensor is commonly used for a variety of industries, including consumer, industrial,
aerospace, military, automotive, and safety-critical processes. They are often used in the
following applications:

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Complete Environmental Shipment Monitoring

• Live Cargo Shipments

• Museum Monitoring

• Highly Expensive Fragile Equipment Transportation and Monitoring

• Aircraft Turbulence / Flight Data Recording

• Aircraft Takeoff and Landing Recording

• Endurance Testing

• Fragility Testing

• Crash/Impact Testing

• Assembly Line Monitoring

• Brake Testing

• Laboratory Drop Testing

• Machinery Monitoring

• Railcar Coupling Impacts

• Container Testing

• Insurance Claims

Examples of Use

Below are some examples that illustrate shock recorder concepts:
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XAMPLE 1

A person standing on earth is experiencing a g-force of approximately 9.8 m/s2 due to the
earth’s gravity. The magnitude of a shock is the multiple of g due to acceleration. At earth’s
gravity (9.8 m/s2) the person is experiencing 1g. If for example, the mass of this person is 85
kg. Then the force upon this person is 837 Newton’s (kg X m/s2) (85kg X 9.8m/s2). The same
person in a racecar accelerating at 3g’s is effectively experiencing a force of 2,511 Newton’s
(837 Newton’s x 3g).

*

for more details see http://www.madgetech.com/dynamic_site/view_product.php?itemnumber=SHOCK101

UltraShock & UltraShock –EB

(EB = 10 year Extended Battery)

MadgeTech Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

201 Route 103 West
Po Box 50
Warner NH 03278

Complete Environmental Monitoring: UltraShock DOC-AN00001-00 REV B 2007.07.11 page 1 of 9

Application Note

EXAMPLE 2
A rocket engine is being transported a long distance with a new shipping company. After the
engine has arrived at site B, the user downloads the data from the shock logger and discovers
that the engine has experienced a shock of “2g”. If the shock value was being examined for
this rocket engine, which has a mass of 7,000 kg, experiences an acceleration of 2g, the net
force applied to the object is 137,200 Newton’s (kg X m/s2). In this case, the rocket engine has
a maximum force specification of 100,000 Newton’s. With the shock data in hand, the user
knows that the rocket engine’s transit exceeded specification and the new shipping company is
disqualified.

How to Use the UltraShock in the Real World

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XAMPLE 1 (MECHANICAL STRESS)

A sensitive microscope with a lever arm is determined to support a maximum mass of 250
Newton’s on the microscope end (opposite the base). The user knows the microscope has a
mass of 15 kilograms. While this microscope was being shipped, the microscope end was
subjected to 3.4 g’s. The user wants to determine the amount of force that was applied to this
microscope to determine if it had been damaged. In this case, the user is solving for force. So,
F= mg = (15kg) (3.4g X 9.8 m/s2=33.2) =499.8 Newton’s (kg X m/s2). Upon downloading the
data for this application, the user would be able to determine the exact time and data value of
which this microscope was subjected to 3.4 g’s.

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XAMPLE 2 (SHIPPING)

Qualifying a new shipping company is a perfect application for an UltraShock. An UltraShock
recorder is being used to record the shipment of military ordinance that is sensitive to
temperature, pressure, humidity, and shock. The ordinance has the following maximum
specifications: temperature 55°C; pressure 25 PSIA; relative humidity 90%, shock 10 g’s. The
ordinance appears to have arrived safely at its destination, and the personnel at the site remove
the UltraShock to download the data. Upon downloading the data, the personnel find that the
shock, humidity, and pressure are all within specification. However, the ordinance was exposed
to a temperature of 57°C. The user can now conclude, based on the UltraShock data, that this
shipping company is not adequate for shipping military ordinance.

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XAMPLE 3 (INSURANCE CLAIM)

The UltraShock data logger is frequently used to ensure the supply chain and shipping process
protects the value of the goods under transportation. Often a user will want to attach a device
that records shock to a shipment to ensure it reaches its destination unharmed. In this
example, the user receives a large shipment (500) of work benches. Seeing some damage to
the shipping crate, the receiver decides to not accept the shipment until the data from the
UltraShock is analyzed. After downloading the data from the UltraShock, the user is able to
determine that at 2:33 p.m. three days ago, the shipment container the desks were in was
exposed to 45 g’s. Without even opening the goods, the shipment was rejected. If the goods
had been accepted, a claim could have been filed with the shipping company using the
UltraShock data as evidence.

Sample Rate vs. Reading Rate

When the UltraShock is recording data, the shock data is constantly sampling at 512 times a
second (every 1.953 milliseconds or 512 Hz). However, it is impractical, and largely
unnecessary, to record each shock sample. Instead, the Ultrashock records the peak value (the

MadgeTech Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

201 Route 103 West
Po Box 50
Warner NH 03278

Complete Environmental Monitoring: UltraShock DOC-AN00001-00 REV B 2007.07.11 page 2 of 9

Application Note

furthest from 0g whether high or low) seen over the reading rate (set by the user). As an
example, if the reading rate is set to 2 seconds, the UltraShock will sample the X, Y, and Z axis
accelerometers 1,024 times and then write the peak value of each axis sampled to non-volatile
memory.

In regard to temperature, pressure and humidity samples: If the sample rate is faster than 2
seconds, temperature, humidity, and pressure will sample at 2 seconds. If the sample rate is
slower than 2 seconds, temperature, humidity, and pressure is sampled within 2 seconds
before the sample is written.

One artifact of this sampling technique is that the data timestamp reflects the data preceding
the time stamp. To illustrate, if there was data with a sample rate of 1 minute and a shock spike
time stamped at 12:01:00 then the actual spike could have occurred anytime between
12:00:00 and 12:01:00. The temperature, pressure and humidity samples would have been
taken approximately between 12:00:58 and 12:01:00.

The vector sum (the forth shock channel) is calculated in the MadgeTech software and is the
vector sum of the x, y, and z axes.

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Vector sum =
where X = X axis reading, Y = Y axis reading, Z= Z axis reading.
Vector Sum, X, Y, Z are all in gravity units.

This is automatically displayed, along with all readings, to provide the user with the overall
acceleration of the equipment or shipment being monitored.

How to Change the Reading Rate

The reading rate on the device can be set through the MadgeTech software. The reading rate
is the period at which the UltraShock records a peak value from previous data and then records
it to non-volatile memory. Before the device is started the user can specify the reading rate to
fit the application. The reading interval records from 64 readings/second to 1 every 5 minutes.
As previously stated, the sampling rate is a continuous 512Hz regardless of the reading interval.
The UltraShock records the peak value (farthest from 0g) per every sampling rate.

Choosing the Right Reading Rate for Your Application

The reading rate will vary depending on your application. For applications requiring a high
reading interval, such as a cargo shipment, a reading rate of 5 seconds may be suitable. With a
5 second reading rate, the Ultrashock can record approximately 240 hours, or ten days worth
of data. For applications requiring a medium reading interval such as vehicle monitoring, a
reading rate of 30 seconds may be adequate. Applications such as impact testing may use a
reading rate of 64Hz, which would yield excellent shock resolution.

Other important factors to consider are battery life and memory capacity. For example, an
UltraShock set to a 5 second reading interval will yield roughly 10 days of data before the
memory capacity is reached. Furthermore, a Shock101 at a 5 second reading interval will yield
roughly 20 days of data. It is important to determine the proper reading rate for your

application for if the logger is set to an excessively fast reading rate the battery may run out of

zyx ++

MadgeTech Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

201 Route 103 West
Po Box 50
Warner NH 03278

Complete Environmental Monitoring: UltraShock DOC-AN00001-00 REV B 2007.07.11 page 3 of 9