| ??? 03/21/07 10:07 Modified: 03/21/07 10:12 Read: times |
#135484 - The fundamental question: Responding to: ???'s previous message |
How can it not fit your application - unless you don't actually have a sinewave?<p>
It is quite likely that the OP doesn't actually have a sine wave (line voltage is notoriously non-sine-like), but without hooking up a scope or similar there's no way of telling for sure. If no scope is available, then filtering the ADC values to reduce the harmonics may be one approach. If the RMS values become closer to what they should be, then that's a good indicator for the input signal being distorted. Another way would be to feed an artificial sine wave into the algorithm (either with a signal generator or by digitally generating one). Yet another thing to consider would be the algorithm that calculates the RMS voltage. In the given examples, the ratio of P-P to RMS seems to be oddly close to 2:1 ... |
| Topic | Author | Date |
| Calculate Rms voltage | 01/01/70 00:00 | |
| Eh??? | 01/01/70 00:00 | |
| Calculate Rms voltage | 01/01/70 00:00 | |
| Measuring RMS | 01/01/70 00:00 | |
Watch for noise | 01/01/70 00:00 | |
| The fundamental question: | 01/01/70 00:00 | |
| Calculate Rms voltage | 01/01/70 00:00 | |
| Scope | 01/01/70 00:00 | |
| Calculate Rms voltage | 01/01/70 00:00 | |
| integers? | 01/01/70 00:00 | |
| Calculating RMS | 01/01/70 00:00 |