That should be ok then.
I wasn’t saying that directly, but matching your feed to the data updates is key to using fixed interval feeds.
If the data can only change half hourly (HH data is a common metering standard) then there isn’t much value in sampling or saving more frequently. A 30min feed would be ideal if you only update the inputs every 30mins.
Maybe you can use the HH to trigger the publish to emoncms? Or just arrange things so that the 30min update happens every 30mins around 10s after the data is due, if the HH data is reliable enough.
I believe there is a emoncms Mqtt api that you can submit a timestamp with the data (I’m sure @borpin will be able to confirm) if you used that option you then have absolute control over the feed data as you can dictate the timestamp to align exactly with the feed time slots regardless of when the data lands or takes to reach emoncms, ie every datapoint timestamp could be an exact multiple of 1800 secs, even if it arrives 30s later than expected. I have used this method loads and discussed it here on the forum. I call it “harmonised” timestamps.