Relay Testing with State Machine

Hi,
Yesterday I very kindly had some help from "crossrulz" in setting out the following procedure. Today, the National Instruments representative called and said I should implement my programme as a "State Machine", which I have attempted in the programme attached. I was wondering how I might now implement the procedures 3 to 5 in this State Machine format as it seemed very complecated in the brief time we had.
What I am trying to do is test relays, using an automated test procedure.
The procedure takes the following steps:
1. A NI9472 DO card and transistor drive turns the relay on/off via energising the coil (needs the time period to be variable).
2. Counts how may cycles the relay contacts have operated, this will easily be in excess of 100,000 cycles.
3. Every 100 cycles (again variable), the contacts are held closed, the load circuit (the current the relay is switching, which will be 15A at 30V) is disconnected, via another relay and a measurement is taken via a separate four wire method. This consists of a 6V supply being placed across the contacts (switched in again via a relay) with a 1A current flowing through the contacts, the voltage drop across the contacts is then inputted into the NI AI NI9219 card (this is in the region of 10’s of mA) and is directly proportional to the contact resistance, which is what I want to measure.
4. The measurement is taken and stored and the measurement circuit disengaged, the load circuit re-engaged, and another 100 cycles is counted before the process goes back to stage 3.
5. This process goes on until the relay fails and hopefully a large set of contact resistance data is gathered.
I have no real experience with NI Labview.
I have looked at the basic academic tutorials and have come up with the following programme for stage 1, however I can't get the DAQ Assistant to output every cycle
Would this be a very difficult programme to implement for the novice? The academic tutorials seem straight forward but when I try to do someting it seems very difficult.
Hoping someone may be able to help, thanks
Andy
Solved!
Go to Solution.
Attachments:
Relay Test State Machine.vi ‏207 KB
Relay Test State Machine.vi ‏207 KB

Hi James,
I've tried to implement some logic as suggested. I can now get the 1A coil to engauge after the nth cycle and I think it's taking a measurement, but can't seem to get the 15 A coil to disengauge at the same moment, which is crucial else the measurement will be across 16 A rather than just the 1 A. Any ideas? I just want to get it working so we can get started with testing.
I'm going to get my supervisor to book me on a course at Newbury for future projects, it's very difficult to pick up of your own back.
Kind regards,
Andy
(Helps if I attach it)
Attachments:
Relay Test State Machine.vi ‏209 KB

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Hello
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Rajab84 wrote:
Thanks apok for your help
even with pressing start it keeps running on wait case
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Attachments:
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screenshot2.jpg ‏300 KB

It looks like your shift regsiter might not be wired correctly.
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braxat2000 wrote:
Hi,
Thank you everybody for your kind help.
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I am implementing my application using state machines, and I have the following problem.
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Thank you Ravens Fan, I did not really understand your message. I have a simplified version of what I am trying to accomplish.
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Attachments:
example.vi ‏26 KB
example control.ctl ‏5 KB

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Message Edited by JoeLabView on 07-08-2008 06:47 PM
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OPERATING SYSTEM - [ MS windows 7 Home Premium 64-bit SP-1 ]
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This is with state machine alone
Abhilash S Nair
Research Assistant @ Photonic Devices and Systems lab
[ LabView professional Development System - Version 11.0 - 32-bit ]
LabView Gear:
1. NI PXI-7951R & NI 5761
2. The Imaging Source USB 3.0 monochrome camera with trigger : DMK 23UM021
OPERATING SYSTEM - [ MS windows 7 Home Premium 64-bit SP-1 ]
CPU - [Intel Core i7-2600 CPU @ 3.40Ghz ]
MEMORY - [ 16.0 GB RAM ]
GPU - [ NVIDIA GeForce GT 530 ]
Attachments:
Control 1.ctl ‏6 KB
Control 2.ctl ‏6 KB
Motor-UNI_Directiona Dev 3-TIME_ANALYSIS-2.vi ‏54 KB

State machines caveat

I have been using the state machine design pattern in programs for a
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This sounds to me like a possible source of errors, that should be
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Do you have any experience or theoretical frame to enlighten these
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Hi,
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Using these rules, I can put the entire program on paper, without any
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Still, I have to transfere information between states. This 'information'
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visible to the end user), a GLI, buffers, ini file reference, or whatever. I
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fastest to use (for me), and easiest to debug (IMO).
Regards,
Wiebe.
"O. Zimmermann" wrote in message
news:[email protected]...
>
> I have been using the state machine design pattern in programs for a
> while. In this technique, it is a common practice to define boolean
> switches to trigger actions in the next iteration of the machine (eg.
> "TurnLaserON", "Quit", "Compute", "SetAlarm1"...). Thus, the boundary
> between data and processing is easily trespassed.
>
> This sounds to me like a possible source of errors, that should be
> limited by some design rule of thumb. I tend to believe that boolean
> triggers in state machines should be looked at with the same precautions
> as a "GOTO" control structure.
>
> Do you have any experience or theoretical frame to enlighten these
> considerations ?
>
>
> oz
>

Allow state machine while loop to end only in 1 of the states?

What is the best way to ensure that the while loop that surronds state machine case structure only ends in a certain one of the states?

I have solved the problem of having the VI not stopping (apparently it was due to an event structure). However, now I have another slight problem. I need the state machine to terminate on either of two conditions:
1) If a stop button is pressed
OR
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As I have implemented it so far the VI terminates because of the second condition and does not allow me to terminate it by pressing a 'Stop' boolean button. I know that this might be a bit fundamental and simple but I'm new with state machines on labview.
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Attachments:
State machine.vi ‏21 KB

How to use a event structure with a state machine

First, I would like to inform you that I only work on LabView part time, and have much to learn. Anything I do learn, I usually forget until I need it again, because I only work on it part time.
Using your StopWhileLoopMOD[1].vi, I am trying to put a state machine inside the event structure.
Related link: http://forums.ni.com/t5/LabVIEW/How-to-stop-while-loop-in-Event-case/td-p/465564/page/2
Here is my application: on the front panel, the user can select any combination of 7 different tests. I have created cases to perform each step of each test in the correct order, but if the user presses stop, the tests won't stop because some of the cases have a while loop inside the event structure (like you mentioned is a bad idea). The user should be able to stop the test, reselect tests to perform, and re-start the tests.
When the start button is pressed for the event structure, I need all the cases to run in the proper order, unless stop is pressed.
In the past I have indexed an array and used that to run the state machine, but it won't stop immediately.
I have sub VIs that are built in while loops because the outputs of the product needs time to stabilize.  The state machine stops and waits up to a certain number of iterations. If it passes the test, the while loop stops and the next state starts. If it takes too long, it exits and reports an error. Maybe I need to just use the state machine and not an event structure?
Is there a good example of an event structure?
metzler CLAD
Solved!
Go to Solution.

I'm not sure exactly what you are asking, but it sounds like you want to script a bunch of tests and if the user says stop, to immediately stop the current test and abandon the others? I'm going to assume that you know how to clear the array so that it will abandon the others, so I'm guessing that you are having trouble abandoning the current test? If this is indeed the case, then the problem is that you are not able to propagate the message from the main VI FP which is the GUI to the sub vi which is the test, where the test may or may not have a GUI (FP visible) of it's own. Threading was the first thing to come to mind, but this may not be necessary using events.
You can do this by passing a refnum of the stop button to the subVI, where you can then add that wait to the event case structure.
I've attached 2 VIs, mainvi.vi which is just a loop displays the count*2 (number of seconds passed since running) that will call subvi.vi and then check to see if the stop button is pressed. mainvi.vi is by no means a state engine, it is just a simple loop for demonstration purposes. subvi.vi just waits 2 seconds and leaves, it is a better structured state engine with an init state to start a poll case to wait for events and an exit state to clean up. You can modify this any way you wish to get it to do what you want. You will note that even if subvi.vi is being executed, it will terminate immediately when the stop button is pressed.
Hope this helps.
A
Attachments:
mainvi.vi ‏17 KB
subvi.vi ‏33 KB

New LabHSM Toolkit - Agile development of complex event-driven maintainable LabVIEW applications with active objects / actors based on a universal Hierarchical State Machine / statechart template.

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State Diagram KIt?
The LabHSM toolkit we are happy to present, makes it possible to
easily create and then maintain complex event-driven applications in
LabVIEW as a collection of HSM-driven active object VIs using a higher
level of abstraction and agile software development methodologies.
These active object VIs are created based on a universal Hierarchical
State Machine ( HSM or statechart ) template. So. all your code looks
similar regardless of its functionality!
We all love just jump to code, right? However, to be good boys, we
need to do design first. Then implement it in code. If the logic is
modified we need to redo the design first and then redo the code. When
using LabHSM where behavior information is abstracted into a separate
HSM data file editable with a supplied editor, there is no need for
coding separate from design any more. The modified behavior becomes
code automatically as soon as the HSM file is saved. Design is code!
The implementation basically follows Dr. Samek's Quantum Programming
paradigm. (see http://www.quantum-leaps.com). However, as already
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some LabVIEW specific code like capturing front panel user events and
putting them into the private Events queue. Communication and
instantiation functions are also rather specific for LabVIEW.
It is available for UNLIMITED PERIOD trial. Please visit
http://www.labhsm.com for details and download. The site also contains
references which you may want to check to learn more about
hierarchical state machines and active object computing.
Since this is our debut we will appreciate any comments and
suggestions. Our contact information is available on our site, of
course.
Have a G'day!

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Double Click Property Node not functioning with Queued State Machine

I am writing an application which relies on input from the operator to start different steps in a process of steps. I am using a queued state machine, however I cannot get the Double-Click property of my listbox to function with in this Queued state machine. I have tried Creating a refrence to the Listbox and creating a property node from that refrence. I have tried a property node of the control. The double click functon works only if the queueing is not occuring. It has something to do with the queue but I am at a loss as to what is causing it. Any help would be GREATLY appreciated. I have attached a simplified version of the state machine with the double click function. Thanks for any help on this. It is written in LV7.1
Attachments:
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Hi
Its Simple....
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see the attachment...
now laugh at your small mistake... (even i have the habbit of making such small mistakes ;-) )
Message Edited by Tushar Jambhekar on 01-11-2006 11:38 AM
Tushar Jambhekar
[email protected]
Jambhekar Automation Solutions
LabVIEW Consultancy, LabVIEW Training
Rent a LabVIEW Developer, My Blog
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I have defined a finite state machine: pb with button : they need to be click twice

I have defined a finite state machine and also defined a call to a C dll enabling to kill processus since in my state machine I have to sequence several exe and being able to interupt them (This is the goal of mu manageProc dll)
for the moment I make my integration test with the notepad.exe process
the create and kill seems to work
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I have also used glabal variable and an event controller ( without that I was unable to get ffedback oo buuton click
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Is my problem due to the use of a shift register
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Attachments:
Spectro State MAchine .vi ‏77 KB

Thibaut,
You should put the event structure into its own parallel while loop rather than sharing the loop with the state machine. Typically the terminals of the controls will be placed inside the event case where they are read. At least inside the loop.
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Producer Consumer with a state machine within the consumer

Hi All,
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3 packet type 1 parsing - parse data and store the remaining data it leftOver array. Go to exit state.
4 packet type 2 parsing - "" ""
5 packet type 3 parsing - "" ""
6 exit - leave this state machine and fall back to the consumer while loop.
After it exit I think it should fall back to the consumer while loop and dequeue more data and enter the state machine again to build a new array with the dequeued data and leftover data. It seems to work when I trace the execution using the Highlight execution feature, however when I run this all at full speed, it seems to go into the consumers 1st and 2nd states back and forth and not completely go through the state machine.
I tried adding in a delay in the producer loop to give the consumer loop time, but I didnt notice any difference. Is it possible that my dequeue element is retreiving more data while im still in the state machine, causing the execution to leave the state machine before it finished all states?
Is there a better approach to take to solve this problem. Basically I need to read data at a 1,000,000 baudrate and parse it as quickly as possible so that I can break it up into 3 different packet types, write the data to a file, and graph the actual data (header info removed) in realtime. I need to also ensure that I am not losing any of the collected data. Data loss cannnot occur.

A couple of things more to go along with Ben's pointers:
You convert your data from a string, to a U8 array, to a Hex string array in the producer loop, then convert back to a integer to determine what to do with it. In the process, you create two or three copies of your data, slowing yourself down quite a bit. The code would be quite a bit more efficient if you left the data as a U8 array. You can change the format of the controls and indicators to show hex values instead of integer by right clicking on them and selecting Format and Precision...
Your search code is fairly inefficient. I made a whack at making it a bit better. See attachment below.
If you continue to run into race conditions, you can debug them using a calls to the Windows debug write sprinkled liberally about your code. Check out the post here for more information.
Don't let your lack of format LabVIEW training stop you. The biggest thing to get is the data flow paradigm (aka data is wires, not registers). Once you get past that and learn how to pass data around using shift registers, queues, events, etc, you are most of the way to mastering LabVIEW. The rest is just learning the plethora of functionality LabVIEW gives you (yes, I have reimplemented LabVIEW native code more than once in the process of learning).
Let us know if you need more help.
This account is no longer active. Contact ShadesOfGray for current posts and information.
Attachments:
serialUtil_V3_DFG.zip ‏137 KB

Other events interfere with abort for state machine started by an event

In the attached VI there is a state machine that is triggered by a boolean “start” change event. There is also a boolean “stop” that stop the state machine, a numeric “voltage” that has an event handler and a boolean “exit” that has an event handler.
The stop button works as expected unless if the voltage value is changed before the stop button is pressed. I was thinking this might be because there is an event for the voltage value change but there is also an event for the exit button value change and the problem does not occur if the exit button is pressed before stop.
If anyone could explain the reason I am only running into the problem with the voltage value change and/or how to properly implement the stop/abort function I would appreciate it!
Thanks,
Dave (LabVIEW 7.1)

Well that certainly solves the problem I was having! The case in a while in a case in a while reminds me of the 10-level deep if statements I used to end up when starting C programming. I guess the inner case/while are required for the state machine and the outer while is required for the Producer / Consumer. I always find myself thinking in terms of "if/then" statements and the case/comparison took the place of that.
Regardless, problem solved. If anyone has tips on how to make it (attached) look better, please post them!
Lynn, I wasn't quite sure about your instructions on passing the exit and stop commands through the queue. I went with the idea of keeping the long-running loop separate. I know I still have a bit more to work out such as use of exit button while state machine is running, and the stop button only works in between state machine iterations.
Message Edited by davey31415 on 11-27-2006 07:04 PM
Attachments:
PowerfoldMeasStat.vi ‏158 KB

Relay Testing with State Machine

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