[Greg McKaskle]

I won't claim to be an authority on the LV-RT side of this, but I can help out a bit.

The ms timestamp in LV is very portable and has been in LV since the mac days. It is often used for simplicity when doing slower I/O and timing. Often, NI would have a card on the bus with a better time source that was synched to the I/O, but it would generally need to keep that timer operation controlled by the driver or the board. Bringing out out to user code in the loop would generally not make sense.

RT OSes change that. You'll find there are numerous clocks and ways to access them. The simplest step is to use the RT Tick Count. In the attached image, it is configured for microseconds and I did a quick jitter test at time critical priority. It is zoomed in, but this is how it looked for the 100,000 iterations I took. Again, I'm not the authority, but this looks like it is based on the OS timer and clearly has some overhead. But it is a simple drop in replacement of the ms ticks and works for the OP question.

For the PPC timer, I think you would use RT Get Timestamp.vi. I say think because I now realize that I don't have all of RT installed. I have much of it synched from a source server and not all of it is functional. If you read the help on the node, there is an example at the bottom for measuring an operation using this node. But I can't run it to give data. I'm curious to see if typical FRC install can.

For the FPGA timer, access from RT code is via the serial bus and while available, the better use of this timer is within the FPGA circuit itself. This gives you implicit access to the 25ns clock that is driving your circuit.

Greg McKaskle