Other Parts Discussed in Thread: SFRA, CONTROLSUITE
Hi,
I like SFRA library for its great help optimizing 500kHz current control loop. But I would like also to use SFRA for slow 16Hz temperature-fan loop or ~100-200Hz temperature-TEC loop. Are there any low/high frequency limits in SFRA? I don't see this information in SFRA pdf. Can SFRA work for temperature control, where feedback always drifts up/down because of external factors?
And here's a problem:
I would like to start from 0.1 Hz, since FAN isn't fast thing and FAN PWM is limited to 16Hz. SFRA lib seems generating starting 0.1Hz frequency waveform well, I also clearly see injection response in temperature ADC, doble checked feedback variable and inject/collect calls. But SFRA kind of freezes forever and doesn't advance to next frequencies. Since there's nothing about frequency limits in the SFRA doc, I thought perhaps 0.1Hz is a problem? But I'm using floating point variant, also SFRA injection for 0.1Hz is working! I tried changing starting frequency to 10, 100Hz, almost always it takes ages to advance, in best case it takes few minutes to step to next frequency.
I tried 500kHz injection. It was better, but sometimes it takes ~10s to advance from starting 0.1Hz, and sometimes step takes over minute. I wonder what could cause such long and random delays? Does SFRA need N whole Finjection periods to collect data? Then why N is random? Is it all because temperature background always slowly drifts up/down, which perhaps upsets SFRA measurements and SFRA restarts for current frequency? Could any SFRA status variable reveal what's wrong? I see no explanation for status and state in SFRA pdf.
Moving from 16 to 140Hz loop didn't help, still n random minutes to step.
Thanks,
Edward