FREQUENTLY ASKED QUESTIONS

Some questions come up regularly about Silicon Designs, Inc's MEMS DC accelerometers. Please see the list below for the most common questions we receive and their answers. If you need more information, please check your product's Datasheet or Contact Us for help.

1.  Why does the accelerometer read zero G's when it's in free fall?

All accelerometers are used to measure increasing or decreasing acceleration, and they can detect vibration because it is a change in acceleration between multiple directions.  Free fall, by definition, is a static acceleration, which means the object may be moving, but its acceleration is not changing at all.  SDI's MEMS DC accelerometer technology allows it to measure free fall because it doesn't require any change of acceleration to supply data, and therefore it will report back 0g of acceleration. 

 

2. My accelerometer appears to be broken. When I place it on the desk with the lid facing up, it reads +1G. How do I fix this?

SDI's MEMS DC accelerometers are designed to respond to the Earth’s gravity. If you are on Earth, then you are in a +1g gravitational field.  Turn the device over and you will see a -1g reading, which you can use to perform your own bias calibration of the device.  Visit our Technology page to learn more about how SDI's accelerometers work. Also see the How to Calibrate Your Accelerometer page for how to use this feature for self-calibration. 

 

3. Do I need a charge amplifier or signal conditioning to use my Silicon Designs MEMS DC accelerometer module?

All Silicon Designs MEMS DC accelerometers feature integrated amplifiers, so an additional one is not required. Signal conditioning is optional.

4.  Are Silicon Designs plug-&-play MEMS DC accelerometer modules waterproof? What is their IP designation?
While all modules are considered weatherproof, only Models 2240 and 2480 may be used while submerged. We recommend the protection of the connector from exposure. Please Contact Us prior to use, and we'll walk you through the process. The IP designation of the other modules is IP61. 
 

5. I am using my plug-&-play module in single-ended mode. What should I do with the unused wire?

Leave the wire disconnected. Do not connect the unused wire to ground, as you will overheat the device and cause premature accelerometer failure.
 

6. We have a Silicon Designs Model 2210 in our test lab that is now 17 years old. Can you provide the calibration sheet for it?

Silicon Designs maintains calibration records on file for every accelerometer we've ever built. However, we recommend that you return the device to us for factory recalibration, as 17-year-old calibration data may no longer be accurate or useful.
 

7. I need to attach a label to the wiring of my accelerometer module, but it keeps sliding off. How do I properly attach a label?

The cable has a low-friction Teflon coating. The best way to attach the label is therefore to glue the label directly onto the device's case.
 

8. Is it possible to re-calibrate my module? Do you adjust the accelerometer when you do this? How often should we do this?

We recalibrate modules all the time for customers who continue to use them for many years. We do not adjust the accelerometer; we just provide calibration data for its current state. You can have it calibrated anytime, but more than once a year or two might be excessive. They rarely change much unless damaged.

 

9. Are your parts RoHS compliant?

Surface mount accelerometers contain no lead. Modules contain a tiny bit of lead, but Silicon Designs products are permanently excluded from RoHS, as they are designed to be a part of another piece of equipment that falls under one or more of the following categories:

  • Military

  • Space

  • Large-scale industrial tools

  • Large-scale fixed installations

  • Means of transport for persons or goods

  • Non-road mobile machinery

  • Equipment for research and development, only available business to business

Our Quality page has more information.

10. What about TEDS chips? 

We occasionally get asked about adding TEDS (transducer electronic datasheet) chips into modules that contains information such as serial number, calibration dates, and other calibration factors.  A large number of our customers don't need this, so to keep prices lower for everyone, we don't include a TEDS chip.  End users can still embed a TEDS device in in the cable's connector.  SDI's TEDS Manufacturer ID is 15328. 

Questions?