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## Position from acceleration data in DIAdem

I'm working on a project where I'm measuring the acceleration of a piece of equipment in our plant using 3 single axis accelerometers. I have 2 of them measuring the X axis (to detect when it is swaying from side to side) and one measuring the Z axis (to show when the equipment is moving up and down). I'm trying to use DIAdem to analyze the data, and I've run into a problem when I integrate the raw data to get posisition. Here's a screenshot of what I'm experiencing:

The top channel is the acceleration from one of the X axis sensors, the middle is the 1st integration, and the bottom is the 2nd. I would expect the veloctiy curve to look similar to the acceleration curve, but out of phase by 90 degrees. The position curve should also have a similar shape. What am I missing here? I'm new to using DIAdem to analyze data, so any help is appreciated. Thanks!

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## Re: Position from acceleration data in DIAdem

How are you running the calculations to determine your second and third graphs? Could you post the equations you are using to produce these?

Rob S
Applications Engineer
National Instruments
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## Re: Position from acceleration data in DIAdem

I'm actually just using the Integrate function from the Basic Mathematics menu in the Analysis tab. Then I do a second integration on the results channel of the first. I think I may be missing an offset correction or something...

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## Re: Position from acceleration data in DIAdem

Hi dzehner2,

What are you using as the X channel in the integration dialog?

National Instruments

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## Re: Position from acceleration data in DIAdem

That could be the issue... I'm just using the blank time channel from the accelerometers. Should I generate a time channel in DIAdem?

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## Re: Position from acceleration data in DIAdem

Hey dzehner2,

You could generate a time channel in DIAdem or log the time alongside your acquisition. How are you logging the data?

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## Re: Position from acceleration data in DIAdem

I'm using a NI 9184 compact DAQ chassis with a NI 9234 signal conditioner with analog accelerometers for sensors. I'm using Signal Express to generate a .tdms log file. I've just been using the internal clock for my X-axis when graphing the data. Do I need to create a time channel or use an external clock?

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