I plan to use the 830M1-1000 (±1 000 g) accelerometer in a drop-test set-up and have chosen two readily available support boards:
Could you please verify if:
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These two boards are suitable (and sufficient) for obtaining accurate ±1 000 g data from the 830M1-1000, or if only one of them is actually necessary.
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Any additional components you recommend (filter RC values, decoupling capacitor size, preferred supply voltage, mounting advice, etc.) so that the sensor operates within specification.
Hello,
Welcome to the DigiKey TechForum. I’ll do some research and post the information I find on this.
1: At the end of the day, it’s your responsibility to determine whether or not a given product is suitable for your purposes. We can discuss product characteristics, usage considerations, etc, but the choice and responsibility of selection are yours and yours alone.
That said, the accelerometer in question is a pre-amplified type, capable of accepting a supply between 3.3 and 5.5v and developing outputs which A) are biased to half of whatever supply is provided, B) deviate by ±1.25v from that point when subject to rated full-scale acceleration, and C) have a frequency response that extends out to 15 kHz. These are the basic figures brought to the discussion by the sensor itself; your goals/objectives may bring additional information to bear.
The ADS123REF board is a low-bandwidth apparatus that returns up to 80 samples per second at high resolution. While useful for weigh scales or similar applications that are concerned with signals that are essentially DC in character, it’s unlikely to be useful for studies that are concerned with dropping things and measuring accelerations in thousand-g territory occurring on millisecond time scales. Beyond that it’s an evaluation board–a platform for study of a target device with all its tender innards exposed and vulnerable. Products in the data acquisition family by contrast are designed as tools to be used in service of an outside purpose, with adaptations and protections that make them more suitable for such use.
The InAmp evaluation board mentioned might be a useful tool for interrogating the raw bridge sensor mentioned in your other recent post, but doesn’t do much for a person in context of a pre-amplified sensor output. If anything, one might consider using a standard op amp to provide a bit of gain to better match a sensor’s output range to an acquisition unit’s input range. See this product family for items that might be of assistance toward that end. If one can cope with a reduced measurement resolution however, skipping the extra complexity is likely to be helpful.
2: It’s something of a reflex/habit for hardware designers to place a 0.1uF capacitance on the power supply pins adjacent to any given IC. The actual necessity of this practice in any given instance however often goes unevaluated, because capacitors are cheap.
The ceramic capacitors most often used for this purpose however are A) brittle and B) prone to microphonic effects that could potentially mess with your data. C0G or equivalent types will be least offensive on the latter point, but no capacitor that you’re going to plant on a circuit board is going to be very appreciative of being repeatedly exposed to impact accelerations. If used, a capacitor with flexible terminations, mounted so as to place the solder joints in compression and avoid shear on impact would probably be a decent choice. Also, support the PCB with the accelerometer to avoid flexure, both to keep the solder joints from breaking and to limit the effect of that mechanical structure on the data being gathered.
