What Signal Generator To Simulate Motor Position Feedback Devices?? - Page 1
Forum section: electronics / testgear

author: gby
author_rank: Frequent Contributor
timestamp: September 28, 2015, 01:02:35 pm
content: We have started looking at two channel signal generators and wonder if they are flexible enough to simulate ideal position feedback devices used in motor controls. The functionality that we need is:1. A Quad B Incremental Digital EncoderNeed to output two square waves at programmable phase (ideally 90 Deg) and vary the frequency with the output smoothly changing.By smoothly changing we mean the frequency changes from one value to the next in a step without an intermediate state like f1 to 0 to f2 and Ch1 and Ch2 always stay in locked phase relationship.We would also like to be able to sweep the frequency linearly from near 0 up to 10 MHz smoothly. Bonus points for being to sweep from fstart to fstop, pause and then sweep down from fstop to fstart. Basically, can you do sweep of both channels simultaneously with the phase lock always there?Extra mega bonus points if we can go from "negative" frequency through virtually 0 Hz to "positive" frequency smoothly. "Negative" frequency means Ch2 leads Ch1 while positive frequency means Ch2 lags Ch1. Doubtful signal generators can do this but it never hurts to ask.2. 1 Vpp Analog Sine-CosineNeed to output two sine waves at programmable phase (ideally 90 Deg) and vary the frequency with the output smoothly changing.Same comments about smoothness, sweeping, and "negative" frequency capability as item 1.3. Resolver signals which are Sin, Cosine Modulated by AM CarrierNeed to output two sine waves at programmable phase (ideally 90 Deg) and vary the frequency with the output smoothly changing like the above but AM modulated by anexternalsinusoidal input. Need to create:Ch1: (Vpp)*sin(w1*t)*sin(w2*t)Ch2: (Vpp)*sin(w1*t)*cos(w2*t)where sin(w1*t) comes from an external input and w2 is the generators frequency. External input frequency w1 would be 5-10 kHz sinewave. "Position angle" frequency w2 would be near dc to 2 kHz.Same comments about smoothness, sweeping, and "negative" frequency capability as item 1.Does anyone know of a function generator/arb generator that can do the above? In order of price we are investigating:Siglent: SDG2042xSiglent: SDG5082Rigol: DG1032ZRigol: DG4062Agilent/Keysight: 33522BObviously there is quite a range of costs in the above and we would prefer being the cheaper end of the spectrum.So, does anyone know which of the above, or other, generators can do some or all of the requested functionality?Note that item 2 is similar to producing an IQ signal set.Thanks in advance for any help/advice.gby

author: _Wim_
author_rank: Super Contributor
timestamp: September 28, 2015, 02:11:56 pm
content: I have the DG1032Z, and frequency/phase coupling between channels is not possible when running a sweep (channel coupling is only allowed when no sweep is run, so you have to vary the frequency manually...). I do not have any experience with the other generators, so can't help there.Greetz,Wim

author: H.O
author_rank: Frequent Contributor
timestamp: September 28, 2015, 03:35:31 pm
content: Hi,This is from the DG4000 manual:QuoteIt'll do sine and square and you can of course set the phase relationship between the two to anything you like (ie. 90° in this case) and according to above it can sweep two channels (though I've never tried that). The manual specifically says that modulation is turned OFF when sweep is enabled so I think you're out of luck with the resolver emulation - if there isn't some sneaky trick you can do that I don't know of.

author: gby
author_rank: Frequent Contributor
timestamp: September 28, 2015, 04:17:56 pm
content: Interesting, the lower range DG1032Z Rigol can't sweep both channels simultaneously but the upper range DG4000 series Rigol does sweep both channels with 90 Deg phase locking.Any feedback from Siglent and Agilent/Keysight owners/knowledgeable folks?gby