Why?

The more I think about this the less I understand it :? If the ISS only transmits data each 2.5 seconds, what use is it to pull data at 1 second intervals?

You might have more than one transmitter?

Tinplate will be able to explain…

The reason I originally coded VirtualVP to get sensor data at 1 second intervals was to minimize to possibility of missing a sensor value. The sensor with the most frequent updates is the anemometer with new values every 2.5 seconds. The console normally sends the data packet with all the current sensor values about every 2 seconds over the serial port. This means you typically won’t miss sensor values using the standard methods. However, since VirtualVP is supporting multiple weather programs, it will very frequently need to slip in a command (get console time for example) that doesn’t have to do with live data, and get back a result in between the live sensor data packets. Because the wind samples come from the ISS every 2.5 seconds, but the normal live data packet get sent by the console every 2 seconds, the wind samples will come in at varying deltas from the live data packets. Sometimes the new wind sample will come right after the live data packet is sent out. In that case, if VirtualVP had to send the console a different command 1.75 seconds after the last live data packet, it could have as little as .75 seconds to slip in the command and get the result or it would miss the wind sample that came right after the last live data packet it had gotten. By getting the live data packets every second, it gives VirtualVP more time to slip in other commands without risking the loss of a wind sample.

The second reason for 1 second updates is that it makes the WD (or VPLive) display more responsive. You won’t see as much delay between when a new value displays on the console and when it displays on the PC.

I did some tests, and I could not discern a noticeable effect on console reception whether 1 second or the normal 2 seconds updates are used. This was a concern I needed to insure against since the console reception can be affected by some commands sent to the console.

Steve

Thanks for the explanation, sounds like a good scheme :slight_smile:

Hi Niko,

It certainly seems to work very well for my setup…Hence my suggestion on the other thread to John…

Regards,

Baggins