Miscellaneous Electronic Components
Within each enDAQ sensor there are a variety of electrical components that can affect overall performance.
*Note Slam Stick is now enDAQ
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The enDAQ sensors use high-end SD cards to handle the fast write speed the device requires. These cards are part of Swissbit's S- 300u series. The Slam Stick C has a slower write speed due to the slower sample rate and therefore uses Panasonic's RP-SMKC08DA1 card for 8GB devices, and ATP's AF1GUDI-OEM for 1GB devices.
Please note that Mide has only qualified these specific SD cards for operation with the Slam Stick. Although there are many other cards available, they often don't have the required write speed and/or temperature range. Therefore they can cause the device to be unable to properly record data which will result in blocks of time with no data.
That being said, customers often look to replace the SD card anyways. That being said, if you'd like to switch out the card you can follow the steps listed below. Please note that the warranty will be voided.
- Make sure you are properly grounded to avoid ESD.
- Unscrew and slowly lift the top plate.
- Locate the micro SD card.
- Carefully slide the SD card backward until it lifts up.
- Remove and replace the SD card.
- Repeat steps 1-4 in reverse order.
Although the Slam Stick devices operate as USB storage devices, they do not provide the same high speed USB transfer rate. This is due to the fact the device’s onboard memory is not directly accessed by the PC, it must “go through” the internal CPU. Expect transfers of large files to take several minutes. The transfer speed currently is 500 kB/s.
The enDAQ sensor each have analog low-pass filters to prevent aliasing. But these filters can also be utilized to reduce high-frequency vibration data that may not be a concern to the user. The filters are part of Maxim's MAX7400 series, all are 5th order filters. The enDAQ sensor uses a Butterworth filter, the enDAQ metal version uses a Bessel filter. For more information on filtering, visit our blog.
Timestamps are generated from Abracon's ABS06-32.768KHZ-1-T oscillator which has a frequency tolerance of ±10 ppm. This means over the course of 1 week (604,800 seconds) the timestamps will be accurate to within ±6 seconds.
The USB transfer speed on the device is 500 kB/s. This speed can be increased marginally with the update to the processor planned for release in May 2019 to 1 MB/s.