Is it Possible to Sync Waveform Generator to Mains AC Voltage

[DFR]

Hello,

Is it possible to sync the waveform generator to a mains ac voltage source. I'm trying to put two signals into a comparator to generate two squarewaves for phase angle measurement. One signal is from the mains ac source, the other from the ad2 waveform generator. When i do this i get drift on the ad2 waveform. Is there a way to sync them together? The ad2 is set to 50Hz (UK) but it doesn't stay in sync.

Thanks

D

[attila]

Hi @DFR

It is not supported directly since the AD2 is supplied by 5VDC, from USB or auxiliary supply.
The AWG could be triggered by external signal which could be derived from mains AC.

[DFR]

33 minutes ago, attila said:

Hi @DFR

It is not supported directly since the AD2 is supplied by 5VDC, from USB or auxiliary supply.
The AWG could be triggered by external signal which could be derived from mains AC.

How would I go about doing that? For context, the ac mains signal is stepped down to about 300mv. I'm trying to use the ad2 waveform generator to supply a signal of the same amplitude at the same frequency in sync with the stepped down mains ac signal.

[zygot]

Be very careful using a transformer to make your mains "voltage compatible" with digital logic. Your mains can have significant excursions from nominal operating conditions that might destroy your digital hardware.

One way to do this is to design a circuit that senses zero crossings of the mains voltage. I highly recommend using optical isolation for any signal coming out of such a design before getting connected to any digital logic. This is not an uncommon problem to solve, so it's been done before. Just be careful about using anything that yo might find on the internet. Generally, some ground reference is required to determine where a zero crossing occurs. This should give you pause and raise some red and yellow flags. If not, perhaps you can find some hardware where it's been done safely. Ground and mains are not good things to play with. At a minimum you need to prevent conditions that are deadly for digital hardware such as over-voltage spikes due to lightening or other events. Also, limit current considerably. This is not something to play with experimentally.