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| All about Keithley DMM7510. Bugs and features, recipes, advice, notes. |
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| MegaVolt:
--- Quote from: Kleinstein on June 16, 2020, 01:52:00 pm ---It is more like odd how they implement this. I could understand 1 µs or 100 ns as the clock used. --- End quote --- Everything turned out to be much simpler. A lot of decimal places is just math. In reality, the integration time directly depends on the 48 MHz oscillator according to the formula N = 300 + k * 400 clock cycles of the oscillator. This is true for a network frequency of 50 Hz. Does this formula change for the network from 60 Hz I can not check :( The consequences: 1 NPLC is not exactly equal to 0.02c it can be or 0.0199979167 s or 0.0200062500 s And I also understood why the generator is 48 MHz and not 50. 50 MHz is badly divided by 60 :) |
| MegaVolt:
I hurried. The formula 300 + k * 400 applies only to the numbers on the screen. Real accumulation time has a different formula with the same step. Those. what is shown on the screen does not match what is set physically :palm: :palm: I will continue the investigation. Students who programmed this device should be fired :( |
| MegaVolt:
Here is a table of what happens in the device. It's hard for me to explain the logic of what is happening. The selected integration time is not even in the middle of the range. But eat and plus. If you set the integration time as a multiple of 8.33 (3) ms, then the displayed and real time will coincide. |
| Kleinstein:
The 8.3 µs make some sense as the period of the run-up phase feedback. One is not limited to these steps, but it makes things easier. So setting the integration time in ns steps is a bit dishonest. Only 8.3 µs steps could be slightly limiting in some cases, but is not that bad. |
| MegaVolt:
--- Quote from: Kleinstein on June 26, 2020, 05:22:42 pm ---The 8.3 µs make some sense as the period of the run-up phase feedback. One is not limited to these steps, but it makes things easier. So setting the integration time in ns steps is a bit dishonest. Only 8.3 µs steps could be slightly limiting in some cases, but is not that bad. --- End quote --- Most of all, I don’t like the fact that I have to get these data and numbers myself. I cannot read them in user manual. |
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