Somebody’s always shopping for a DAQ by the bit count, figuring 24-bit beats 16-bit. It doesn’t work that way. Resolution and accuracy are two different things, and mixing them up gets you numbers that look precise but are still wrong. Resolution vs accuracy is worth sorting out before you sign the purchase order.
What resolution actually tells you
Resolution is the smallest change your DAQ can see. It comes from the number of bits and the input range. Split your range into more steps and each step gets smaller, so you can pick up a finer change.
Resolution only tells you how small a step the hardware can report. It doesn’t tell you whether that reading is correct. A card can resolve a microvolt and still be way off.
What accuracy actually tells you
Accuracy is how close the reading is to the real value. Gain error, offset, drift with temperature, the voltage reference, and plain old noise all pull your reading away from the real number.
Noise is a big part of it. If the last few bits are just noise, they’re useless to you. You get a number with lots of digits, but the reading still wanders, so those digits don’t make the measurement any better.
Resolution vs accuracy: what to check instead
Read the accuracy spec, not just the bit count. Look at absolute accuracy over temperature, the noise numbers, and how the range you picked lines up with your signal. That’s what tells you whether you can trust the reading.
Still weighing resolution vs accuracy on a spec sheet? As a data acquisition system integrator in Cleveland, our team specs and builds systems around the numbers that actually matter. Reach out and we’ll help you get it right.
