Loop Delay

[Shah235]

Hi Guys,

I am new in Labview, hope to get an idea how to do this:

I am doing driling process for set of 200 holes.  Each hole takes about 2secs to drill, and distance between holes is about 3 secs. I am interested in getting data for the drilling only, and neglect the tool travel  between holes.

I got the idea to delay the loop(for tool travel)using 'wait unti next ms', which i should set for 3secs. But how to set my loop runs and collect data for 2secs before that?,I set the no of samples to be 1000 with 1khz sampling rate.

Thank you.

[nyc_(is_out_of_here)]

Post your VI.

Sounds like you need to take LabVIEW tutorials.

http://www.ni.com/getting-started/labview-basics/

[James.M]

You should share the code that you have this far, so we have a starting point to help you with.

Yolu also probably don't want to use Wait Until Next ms Multiple unless you know that it will always perform tasks at a multiple of 3000 on the clock, or you're trying to synchronize with something else.

[Alexander_Sobolev · Accepted solution]

Technically it is wait, measure (2k samples, 1kHz), repeat loop. State machine, sequence in the loop, etc.

The problem is in synchronization. You are saying it takes about 3 sec to move and about 2 sec to drill. Error in specifying time of 2 ms on each stage and you are off by a second by the 200-th hole. Programmatically (not real-time) you can synchronize loops (reading data and movement) with precision of 10 ms I would say, not more. Also moving drill between holes takes different time.

I would collect all data, then split them into holes parts if you can (search for peaks, etc, I do not know if there is significant difference between drilling data and movement data. Processing can be done on the fly or after collection.

If you have significant signal level changes - you can try analog triggering = acquire when signal crosses specified level.

Otherwise you need digital signal to trigger acquisition when drilling of each hole starts. 

[Sam_Sharp]

I agree with others - I would try to create a more robust piece of software that detects the difference between drilling/moving or if that isn't possible, collect all of the data and post-process it.

[Shah235]

Thank you your help!

That's what i am currently doing, collect all data and get them post-processed.

[billko]

Is this some exercise?  It feels like using a screwdriver as a chisel.  Is there a reason you cannot use the correct tool - i.e., a CNC machine?