500 microseconds pulse

[frnz]

Hi Everyone,

I need to generate a pulse of 500 microseconds (repeated every 350 mS) and I just wonder if this is possible using the parallel port with LV7.1?  Any sample code will be much appreciated.  Thanks,

Frank

[TobyD]

I believe the only way to get sub ms timing is by using LabVIEW RT or FPGA.

[labviewman]

This would be a piece of cake using a MicroChip PIC and would be much cheaper.

[johnsold]

Trigger a one-shot multivibrator from a much longer pulse (but still shorter that the 350 ms interval). Let the one-shot create the short pulse and software manage the timing between pulses.

Lynn

[lmtis]

How accurately do you need to control the 350ms?

[jdunham]

You can also do it pretty easily with most of NI's DAQ cards.

[frnz]

Hi Jim,

Accuracy is within +/-10% . . .

I was planning to use PIC16F877 thru RS232 interface, but I have to be able to synchronize this pulse with a DAQ 34970A to measure resistance.  Here is the scenario:

Drive a relay with a pulse of 500uS and make a resistance measurement (or any other means, i.e current, voltage, etc) to determine that relay did not switch (stays inactive).  It may be repeated at a rate of 350 mS.

Could it be possible to generate this pulse using C# and measurement studio (I will post this question at MS forum also)?

Thanks,

Frank

[Gabi1]

seing that you have an agilent system, and no PCI DAQ or DIO card, i suggest you follow what Lynn has proposed. a multivibrator is very easy to solder up, and you can drive it from the parallel or serial port.

changing programming language wont make it for you BTW. in Labview, to repeat the task every 350 ms, you can use a timed loop. the inherent software time jittering is expected to be lower than 1%.

[frnz]

Thanks everyone for your input. . . Frank

[AnalogKid2DigitalMan]

Will your relay even actuate with a 500us pulse? What type and or make/model is it?