Detecting multiple events

[DavidIMurray]

Hello

I am working on using sound as a condition monitoring tool. I currently have a system setup where a microphone monitors a set of metal shears. Input is via the PC soundcard. I have a VI setup that listens for the cutting action. It then extracts a portion of the signal, in this portion it should be possible to detect a second sound which is the cut (cropped) metal falling into the bin.

I have the system working such that there are two indicators on screen. One indicator denotes a crop detected and the second indicates that it has been succesful. What I want to do is combine this into a single indicator - i.e. if crop=true and succes=true then indicator =green, and, if crop=true and success=false then indicator=red.

The problem I have is that the two events occur at different times so I need to 'latch' the first crop signal for a period of time while listening for the second event. However I can't seem to create a latch that works.

Any help greatfuly received.

Thanks

Dave Murray

[LV_Pro]

One possibility is to have the first instance's result stored in a shift register (one that is initialized before you are looking for the data), which get compared with the second's result to provide your Pass/Fail. Then the shift register can be reset to its initial state. If you have a snippet of your code that you can show, either actual code or a .jpeg or .png picture of the diagram (please no BMP's) it might help.

P.M.

Message Edited by LV_Pro on 09-22-2005 09:45 AM

[DavidIMurray]

Hi

Here's the code that I currently have running succesfully. Ignore the graphs as they are only for diagnostic purposes. The 'Crop detected' and 'crop succesful'  are the two indicators mentioned previously. I can also post the VI. Do I only need to post the vi file?

Cheers

Dave

[JamesC]

Hi David,

I have created a quick program that will latch the boolean output of your Crop Detection trigger.

You should be able to understand waht is going on, if you do not please post back.

Regards
JamesC
NIUK AE