| ??? 03/13/06 12:51 Read: times |
#112045 - Actually, the choice is only related to Responding to: ???'s previous message |
1) Count number of pulses in one second and multiply into 60
2) Get the time between two pulses and calculate the frequency Actually, the choice is only related to the frequency. If you count pulses for e.g. 1 sec the error will inclreas with decreasing frequency e.g. if the frequency is 100HZ, you will get up to a 1% error, at 1KHz the max error is .1%. With measuring "the time between two pulses", The error will increase with higher frequencies due to interrupt latency. Calculate both for your range and choose what fit the best. 1 rpm? can it be done with a 12mhz crystal If you go for such a precision the readout will become unusable at a higher frequency since it will read differently7 for every display. Motors do not run that stable. I would specify the accuracy in percent. Erik |
| Topic | Author | Date |
| tachometer "which one is best" | 01/01/70 00:00 | |
| > Which accuracy do you expect? | 01/01/70 00:00 | |
| accuracy | 01/01/70 00:00 | |
| Both are acceptable | 01/01/70 00:00 | |
| Actually, the choice is only related to | 01/01/70 00:00 | |
| mobike plug | 01/01/70 00:00 | |
| shooting for the moon | 01/01/70 00:00 | |
| resolution | 01/01/70 00:00 | |
| Cleaning input signal | 01/01/70 00:00 | |
| How do you propose to get the signal? | 01/01/70 00:00 | |
| inductive pickup | 01/01/70 00:00 | |
| cleaning input signal from the spark plu | 01/01/70 00:00 | |
yes, mistype | 01/01/70 00:00 | |
| None of them | 01/01/70 00:00 |