Continuous loop for flat sequence

Hi, I currently using LabVIEW 8.2 and still learning about LabVIEW. I’m doing a project on a FMS model using USB 6501 to run the program and I’m required to run the program continuously. I was given a program from a previous student and I’m supposed to modify the current program. The purpose of the program is to gather stock from the warehouse and place it in a different slot.
I have a sample of the program and layout of the model where the lift is to move to the left and back to the right. I’m currently stuck as I can’t figure out how to run the flat sequence continuously.
Firstly, it would just run once and stop at the right even when I’m using while loop.
Secondly, when pressing the stop button it wouldn’t stop the program midway, it would continue to run until the frame ends. Is there a way to stop the frame when an error occurs?
Please advice. Thanks.
Attachments:
LIFT LOOP.vi ‏288 KB

You definetly have to switch to a reliable architecture!
I think that your application must have several security features to prevent damage of hardware or even humans. So you must not use a program which just moves the lift from startpoint to endpoint without any chance to break the movement!
That being said, i see two approaches:
a) Statemachine
b) Producer/Consumer
The backdraft of Statemachine is its polling character. So you can only react to "worst cases" only within your given timeframe. The timeframe is the polling time plus all latencies including signal delays and similar. This can easily add up to about 1s and more.
Producer/Consumer can possibly react a little faster if it is event based. The backdraft is that you need a rather good knowledge of LV in order to implement this properly.
Another thing for applications like this are latencies created by the OS. Maybe it is necessary (not only recommended) to switch to a RT system or even FPGA in order to keep proper reaction times.....
Maybe it is a good idea to talk about this application with an NI Alliance Member .
hope this helps,
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

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Continuing a loop for a set amount of time

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You have the compare function implemented incorrectly. You need to make sure that the first terminal of the "Greater than or equal" function connected to the output of the sum, and the second terminal to the tick count in the while loop. The first terminal corresponds to x parameter and the second terminal is for the y parameter. So if x is greater than or equal to y, then the loop will need to exit.
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Metronomes, while-loops and flat sequences

I'm making a loop that is supposed to write a poll message to the serial port once every minute and read a message from the same port once every 256 ms. It is supposed to proceed untill a stop button is hit. It is based upon a while loop that contains two different flat sequence structures that each contains a metronome ("wait until next ms").
The intention of thisis that the program goes through the loop and every 256 ms it reads the serial port and every 60 000 ms it sends a polling message. However, the indicators I've connected to the metronomes doesn't seem so show a linear increase in the ms timer. The poll timer occasionally increases a little (in two minutes it might increase 20 ms). The read timer does not increase at all. Poll count increases very irregularly.
Does the flat sequences interfer with each other? Can this loop be changed in any manner in order to work properly?
Attachments:
poll_loop2.GIF ‏13 KB

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How to execute a frame of a flat sequence structure for a specified amount of time?

Hello,
I have a timed loop measuring a resistance value every 2 seconds. I would like to have this timed loop execute for a specified amount of time (e.g. 5 minutes). The timed loop itself is placed within a flat sequence structure so I am concerned that the measurement will be taken once and the next frame will begin to execute, without waiting 2 seconds for a successive reading (and not looping for, say, 5 minutes).
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All code in one sequence frame must complete before the next frame can execute. So as long as your timed loop is setup correctly, the next frame cannot run until your 5 minutes is up (N = 5 minutes/2 seconds/measurement = 150 measurements).
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Timed loop inside a flat sequence not terminating

Inside a while loop there is an event structure. Inside that there is a flat sequence. On one of the frames there is a timed loop that quits after so many iterations. The timed loop finishes but the flat sequence doesn't execute the next sequence. What am I not doing right?

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Attachments:
RTSpider.vi ‏376 KB

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Good morning.
I was working on a report generation vi for my project, and it has grown way too stacked. Loop within case, within sequence etc.
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Attachments:
PIC2.jpg ‏139 KB
PIC3.jpg ‏165 KB
PIC4.jpg ‏142 KB

I tried to move your structures around, but this happened:
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