Microsecond delay

[m-s]

For a measurement, I need to insert a delay of 10 microseconds - 100 microseconds at some point in the execution. Is this possible ? If so, how ?

The code will run on a modern machine with a CPU speed of 1 GHz+, so it should be possible theoretically.

[Christian Mergl]

What OS?

[smercurio_fc]

The speed of the CPU is not relevant here. The OS is, however, as Christian alluded to. While a non-deterministic operating system (like Windows) may have a call to get you a microsecond delay there is no guarantee that you will actually get that. Also keep in mind that the overhead required to actually call those operating system functions from LabVIEW will likely swamp out the actual delay you're trying to achieve in the first place. If you're trying to do this on a non-deterministic OS you may need to consider moving to a real-time OS.

[m-s]

The OS is Linux (Fedora 10) for deployment and OSX (Leopard) for development. Using version 8.6 in both cases.

[Dennis_Knutson]

Since neither is any more deterministic than windows, you cannot do such a short delay in software. What kind of measurement are you doing?

[Christian Mergl]

Like smercurio and Dennis said, with a non-realtime OS you won't be able to get such a timing. Even the jitter is higher then the execution timing you need.

Christian

[m-s]

Its a CELIV measurement where I have a triangular ramp (about 60 microseconds long) followed by a 10-100 microsecond delay at zero bias. I could in principle use a software trigger on the instrument to simulate the delay with empty measurements, but was wondering if I could avoid that.

[Christian Mergl]

Whats your measurment hardware? Is it an NI DAQ device?

[m-s]

The measurement hardware is a PCI GPIB card.

[Christian Mergl]

Well, GPIB (General Purpose Interface Bus) is for communicating with instruments and not a measurement device to acquire signals and trigger an acquisition.

So what instrument is connected to this GPIB card?

As far as I understood your application and the timing considerations you will need an FPGA for doing that.

Christian