Replacing a state machine?

I am fairly new to using state machines and am hoping there is a simple solution to this question. I have one state machine that is saved (ie StateMachine1.ctl). I created a new state machine (StateMachine2.ctl) and want to replace all instances of StateMachine1 with StateMachine2 in my VI. Is there a simple way of changing the state machine without losing all the linked instances?
Thanks.
LWolfe.
Solved!
Go to Solution.

LWolfe wrote:
I am fairly new to using state machines and am hoping there is a simple solution to this question. I have one state machine that is saved (ie StateMachine1.ctl). I created a new state machine (StateMachine2.ctl) and want to replace all instances of StateMachine1 with StateMachine2 in my VI. Is there a simple way of changing the state machine without losing all the linked instances?
Thanks.
LWolfe.
Let's make sure we are using the correct terminolgy here. It seems that what you are calling a "state machine" is really a custom control, probably typedef'd and because it was typedef'd, probably an enum. I like to make mistakes like that, mistakenly calling something by the name of something else very closely associated with it.
So is your question really, "How do I replace one custom control with another?"
In this case, it might be just easier to modify your first control and forget about using the second. Assuming again that it is a typedef'd enum control, modifying the typedef'd enum that is already part of your state machine will ensure that the changes are propagated to all the other places.
Bill
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.

Similar Messages

How do I add new data to the same file in a State Machine?

Hello,
I have a State Machine, with a State where 3 samples of data are collected in a For Loop. I would like to save this data in a file and keep adding new data to the same file each time I get to this state. The problem I'm running into is that each time I reach this State, my old data in the Excel file gets replaced with the new data instead of being continuously added in the same file.
Ive tried Shift Registers but I may not be using them correctly since my file keeps displaying only 3 new data points.
Any ideas will be appreciated!
Thank you, so much.
-Peter

Where should I place these shift registers? Where should I place my File I/O VIs? Is it possible to use the Write to Spreadsheet File VI in this situation?
Ive attached a very simple example of the problem. Thank you.
Attachments:
StandardStateMachine 2.vi ‏16 KB

Using "Enum constant" in state machine.

hallo all.
i bild state machine, with 10 states. i move beetwen the states with Enum constant.
my qustion is: if i want to add/delete some states, why i need to update the Enum constant at every state ?
there is way to update "Enum constant" at one state, and all other "Enum constant"(in other states) will update automatically
thanks

If you save you enum as a type def and replace all of the current occurences of the enum wi the type def, you shoud there after only have to update teh typedef.
1) Find an oocurance of the enum
2) Right-click and change to control.
3) Find control and select Advanced customize
3) Pull down on selector and change from "control" to "type def"
4) Save control.
5) close editor and when prompeted say yes to replace control.
6) Change control back to constant
7) replcae all previous occurances by choosing replace >>> the typedef'd control.
8) Case structure will folow typed def from that point forward.
Ben
Message Edited by Ben on 12-24-2006 03:31 PM
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Simple state machine Where to begin?

Hello
Got a question that is simple for the experienced people here I guess. But don't know where to start..... Here is what I want to try to do:
I have got a lot of inputs, to keep the question simple I have only drawn a few of them but eventually there will be tens of inputs. For now I will only use the front panel and no real IO box (hardware), just to see if I can make a State machine that can handle this "problem" in a organized / proper way.
What I want is to do is read a sensor, for example sensor B1 and multiply it with the multiplication factor (column Process input) and show the result on the front panel.
There will be different types of sensors, some need multiplication, others sensors need just a constant be added to the input before the result is shown in the Result column etc.Of every sensor there will be a lot, so just wiring them all in one place will create chaos, and I don't like chaos (only dr chaos in South park is fun but I would not have him in my labview code either).
Can anyone tell me how to approach this "problem" ?
Thank you for the advice!!

Hello altenbach,
thank you for your reply,
I think the question might not have been completely clear. I can devide the question in different parts I think. I will give it a try lets see
(1)There Will be a lot of sensors and a lot of different type of sensors. There will be sensors that behave:
(A)as a switch Called them Type A in the picture
(B)as a voltage source For example mV per degree celcius
and then there are more
(C)sensors that behave as a current source
(D)and a other type of sensor
ow noooo there are more
and even more
(K)sensors that have got a voltage output but measure something else as B for example a distance.
Of every type of sensor there will be more than 1 sensors. So there could be 10 sensors of type A 8 of type B 15 of type C etc. It would also be nice to ad or remove a sensor after a while.
The sensors need to have a usefull name. Like "Temperature in chamber A". I want to be able to use this name everywhere in the code. So I if I need to process the "Temperature in chamber A" I want to have a human readable name. (type def?).
I think I need to have a other name to indentiefie what kind of sensor it is: temperature, distance etc. This would make it easier to make a subfunction or SM deciding how to handle this information.
So I think the question should be how can I make a big highway of data comming out of the front pannel in one wire, If I have wire's A till K the code will become unreadable. I was thinking of some kind a arry of strucs?
I tried to keep the qestion as simple as possible at first but maybe it made it too unclear I think the question might sugest it will stay a simple program but it will not, it is just a first step.
The first step I want to try is to just multiply a voltage with a number (just to test the functioning of the supper-highway of data).
If I know that that works I will try this superhighway of data in a State machine then the value will to be prosseced in different ways.
After that I hope to have the Hardware IO It is a NON FPGA frame with a few cards in it from NI, cabable of measuring digital IO analog IO etc analog output etc. So at that point the frontpannel will be party replaced for the HArdware IO. As I want to test the software in different stages of development I first wanted to start simple so I could test the written software in different stages of development.
So can anyone tell me how to get this supperhighway of data out of the fron pannel?
I hope the question is a clear, if not just ask.
Thank you for the help so far!!

Making sequence structures a state machine

Hey I would like some help I need to work on changing my code and get rid of the flat sequence structure and replace with a state machine I have attached my code at an earlier state but would like some input on changing it over to a state machine in the sequence at the bottom of the code this program is used to cycle a valve and the sequences need to be done in order .any input would be great.
Attachments:
valve Cycles with temp.vi ‏132 KB

Right click on the Flat Sequence and pick Replace with Stacked Sequence (never would have thought I'd say that.)
Right click on the Stacked Sequence and Replace with Case Structure.
Now a lot of wires will wind up broken. So you'll need to hunt them down and fix them. Those wires will probably need to go to shift registers so there values are maintained for the next loop iteration. Keep a copy of your original VI so you have something to refer back to.
Create a Typedef Enum and define what your states will be.
Start wiring the Enum into a shift register at the left of the loop, then into the selector of the Case Structure. Rename all the cases to what their respective state should be.
Wire enum constants in each case to direct what the next case should be. It will run out of the case structure to the right hand shift register.
Keep working and cleaning still everything is fixed.
Try running your VI to see if it behaves like it originally did.
Now you are safe to start making modifications to make it behave like you really want it to.

Discrepancy between execution time of state machine and flat code

I am trying to optimize the performance of my application, and I've found that the same code executed as a case in a state machine, and flat on the block diagram takes a dramatically different amount of time to run. I'm trying to figure out what I'm missing here. The picture shows a test vi I threw together (the next post will have the diagram image for the "Add New" case of my Buffer Engine.vi - basically the same as what is in frame 5). The fifth frame in the sequence is what I am concerned about. It shows that executing the case in the state machine takes ~700ms, and flat, ~113ms.
Any thoughts?
Chris
Attachments:
Test Times.jpg ‏124 KB

Thanks for the suggestion Altenbach. I had to insert a for loop to replace array subset indivually for each column of new data to place in the buffer, but even with the extra processing, the result was about 80% faster. I guess I'll have to come up with a system to track where to place the data (it was convenient to always drop the data at the end..), but that shouldn't be an issue.
However, this suggestion doesn't address the original concern. The same array resizing was going on in both the subvi and the sequence frame. This improvement should increase the performance of each, but doesn't explain the difference.
As an aside, I contemplated using a queue, but without the ability to dequeue from both the beginning and the end, I don't see how I can use them for this. I want to trash the oldest data, not hold up the acquisition. In any case, I don't think it would be faster because the memory isn't pre-allocated. Now I am considering just storing the data in a control, and passing the reference as necessary. The question is, is reading the value from a control faster than reading from a shift register?
Thanks again.
Chris

How to add a state to an existing state machine?

Hello,
I have a state machine with 5 states. See attached vi (LabVIEW 7.1).
Now I want to add another state ("wait") between state Druck Aufbau and Druck Abbau. How can I do that?
I tried to add a state to the enum on the left and then I noticed that I would have to modify every enum in the vi and the case structure as well.
Is there an easier way?
Greetings Johannes
Using LabVIEW 7.1 and 2009 recently
Attachments:
Hysterese_Disc.vi ‏75 KB

You should replace all enums of the state machine with your type def'ed one. Thus, every change you make will be propagated throughout your state machine. When you need to add or delete states, change the typ def (so the Enum.ctl), and then all the enums will change. Thats the very reason of type definitions. In future, always use type defed enums.
Felix
www.aescusoft.de
My latest community nugget on producer/consumer design
My current blog: A journey through uml

Add an item to all state machine constants

I have a state machine using an enum for the state indicator. In
the current state, the next state is indicated by an enum
constant. If I want to add a state, how can I update all of the
constants? Here is the problem. If I add (or delete) an
item in the selector of the case structure, it is red because the enum
constants do not have that value in them. Conversely, if I add an
item to one of the constants I can "Add case for every value" and add
it to the seletor, but then I have to manually add that item to each of
the other constants. Also, the way I usually create the constants
is to pop-up on the exit tunnel for the enum in the case structure and
"Create constant". Unfortunately, that tunnel retains the choices
of the old enum and the new choice must be manually added. Is
there any way around this? I would like a method that allows me
to add or delete choices at will and have all of the constants
automatically update to match.
Roy

Well LabVIEW has just what you need in the "type def"! The next time you create a enum, right click on it, select create a control go to the front panel, right click on the control and select "Advanced" and then "Customize" to enter the control editor (if you have selected in your front panel "tools", "options", "front panel", "open the control editor with a double click", you can ust double click on the control to enter the control editor). In the control editor you will see a toolbar pull down with the "Control" option. If you pull it down and change to "Type Def" you can modify the control and all copies of it will now get automatically updated, including constants created from the type definition. The strict type def controls the look of the control as well, so it is most often used to make sure that operator interface instances of a control look the same. When you save this new type def it should ask you whether to update all instances, which will update the original control , you will have to go back and make a constant from the new control type to replace that original one, but now every copy made from that one will update when you update the type definition, and you can do that from the constant on the diagram by right clicking and selecting "open type def".
P.M.
Putnam
Certified LabVIEW Developer
Senior Test Engineer
Currently using LV 6.1-LabVIEW 2012, RT8.5
LabVIEW Champion

Any penalty to using one big cluster in a state machine?

I've been working on a lot of small/medium sized state machines lately, and I've gotten into a habit of putting most of my data (single values, arrays, strings, even LVOOP objects) in one cluster that I pass from state to state with a shift register. I just unbundle the data I need in each state, work on it, and bundle it back in for the next state. Part of me says that this is a bad idea - that I should separate the big cluster into a set of smaller clusters that group the data by logical categories. Another part of me says that if I do it that way, I'm just creating needless clutter on my diagram.
So my question is simply this - is there any significant performance penalty for using a single cluster rather than multiple clusters in this fashion? I never run the whole cluster into subVIs, and I never split the main cluster wire, so it doesn't seem like there should be... but I've been wrong before!
Thanks,
Jason

As Norbert mentioned, the answer to your Q is dependant on your data structure. Provided you can do all of your data manipulation "in-place" there should not be any issues. The more complex structures can still be handled "in-place" but you may have to use the in-place operations to achieve this effect. Depending how comfortable you are with those operators, they can complicate the appearence of our code.
If you can'y do everything "in-plcae" and you have a Super-Cluster, then its time for me to Quote Rolf again when he wrote "Once all of you physical memory is filled up with a single cluster, your application is probably going to suck."
So lest say you have cleared all of the above hurdles and still want to use a single SR that has all data for all states. I ask you to carefull examine where the app may go in the future and what type of animal it could turn into. if there is even a small chance that app may turn into something that non-computer users will use (requires robust app to prtect itself from dumb users) the single cluster approach is going to get in your way when the app gets big.
1) If you have to add another field to the cluster, every function that uses that cluster should be re-tested. WE have an app in-house that was developed by our customer and we support. There is an 800+ step proceedure required to re-verify the app!
2) AS more functionality is added you will add more states to your state machine. Personally, I cringe when I see the support developer have to choose from a list of 300 states when working with the Stae machine.
3) You will have a hard time re-using code aside from cutting-n-pasting
4) When you unbundle manipulate and replace, you are in danger of creating duplicate data which will impact performance.
I never went through the formal IS training but my wife did and she has given me the short version to learn how to normalize a DB. There is actually a science to the process that results in only related items being grouped together and if you take to the full exdtreme of "fully Normalized DB", there absolutely no duplicates of data. For LV apps a Fully Normalized DB adds some overhead so I don't go that far.
THe following will ignore using an Object Oriented approach and stick with old-school ideas.
So after I analyze my data structures and group related items together and review who touches what when, THEN I try to wrap-up the data in Action Engines. More often than not, the action will replace some or most of the work done in some states. From your Q it sounds like your "read-mod-replace" constructs can be moved into AEs with little effort.
Now for OOP
I'm still learning OO system design but I have found myself "turning my apps inside out" with LVOOP. By this I mean rather than think that the data AND the function are inside the AE, the data is outside and acted on by what is inside the LVOOP methods. I have been amazed at the degree to which LVOOP can operate in-place, but I digress. There is some arguement/design pattern that says that if you have a function like a test that uses other classes, then you can create a class for the test and slam all of the required object into you need.
Done rambling for now. As usual, if there is anyone out there that want to correct me any of the above, please do so!
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Serial commands with a state machine

Hi,
I am reading with VISA from a serial device. I write to the serial the start character and the device is sending some data.
Now after I read the data I want to stop the sending by writing to serial a stop character. The reading is in a separate loop.
I want to make a stop button that writes to serial and a start button that writes to serial and reads the data. Is there any way to do this without a state machine ?
Btw, is there any examples for a Serial reading and writing state machine ?
Solved!
Go to Solution.

Remove your first while loop. You are initializing the serial port over and over again until you press OK. You only need to initialize once. Put all of the code before the loop. The loop should just delay for a few mS until the OK is pressed. You should always put a dely in a loop so as not to chew up 100% CPU time. Even a 0mS delay will allow the CPU time to do other things.
In the second loop, since you have an event structure, you don't need a delay. But you do need to wire in a value to the Timeout hourglass icon on the top left corner. I typically use 100. Again this is to prevent 100% CPU usage.
Do you understand data flow execution? This means that a loop or block of code or a function will not execute until all of its inputs are present. Your third loop will not start until you press the quit button because you have two wires going from the second loop to the third. These wires will only pass their data to the third loop when the second loop is over (pressing the quit button). When you press quit, the second loop terminates and data goes to the third loop. Now all of the third loop's inputs are present and it can execute. This is not what you want. Delete the wires between second and third loop. Then the third loop will execute from the beginning. The serial read control will tell it when to read and when not to read. You will need to pass the VISA Resource Name to the third loop by using a Local Variable. From your statement, it sounds like you already did this. Pass a no error condition into the third loop also. You can make one or use a local variable of error in.
In the third loop, you have the VISA Close inside the loop. This is not good. The VISA session will close before you read. Move this to after the third loop. Then it will close only after the third loop stops.
After you delete the wires between loops 2 and 3, you will have to merge errors from the second and third loops to make sure you catch all errors.
In each one of your loops, replace the VISA Session terminals and Error terminals with shift registers. This is good practice and is recommended by NI. With terminals, if there is an error on one loop iteration, it will get lost because the next iteration takes in the original no error condition from the left side. With a shift register, the error gets propogated to the next loop iteration. If your loop executes zero times (For Loops can do this), the output of the VISA terminal will be a null value and the VISA close will cause an error. With a shift register, even if the loop does not iterate at all, the VISA Session value on the input will be propogated to the output.
I think that is enough for now. Please make these changes and re-post your vi. You are making good progress.
- tbob
Inventor of the WORM Global

Labview State machines Edit Items

Iam using a state machines, Iam having a problem with updating new items in the state machines..
What happens when I right click on the enum attached to the shift register and try to add new item to it..
the cases change to numbers istead of actual choices..
what can I do to fix this.
Thanks

R U Sure
I can do it
Thanks & Regards,
Kunal Raithatha.
CTD - CLAD (I wish I can take off that A, and maybe use it later to replace D :-)
Easy Tip :- "To copy an image to a VI icon, drag the image file and place it on the icon
located in the upper right corner of the front panel or block diagram" ...If you know any
more reply back.
Attachments:
SK0480.vi ‏5 KB

State Machine Demo

Hi Folks,
I am a newbiew LabVIEW developer studying & working towards my CLAD certification.
I already took LabVIEW Basics I & II and I decided to make a simple state machine (please see attached VI).
I was hopping if there is anyone out there who find a way for the VI be optimized so I can see my weakness.
ThanX in ADVANCE!!!!!
Attachments:
StateSimulatorfromEE428.vi ‏71 KB

Overly complicated and convoluted is the word.
I haven't even tried to undestand what you are juggling with all these string operations, but there's gotta be a better way!
Case 4 and 5 are identical except for a diagram constant. They can be comined into one case.
"state operation" is a control, but you are constantly writing to it via local variables. This mean it cannot be reliably operated, because the set value could be reset before it is used due to race conditions.
It is confusing that you replace the "state" of a typical state machine with a "state operation", while the "state" is actually in a string that does not really influnece operation. Whatever you have is not a state machine.
In state operation=2 you delete from the 2D string array, but later you always seem to iterate over 9 elements (one too many to begin with) in the inner while loop.
Since the 2D string array can shrink but never grow, you might stop the program once its size reaches zero.
You write to a local variable in virtually each state, it would be more reasonable to pull this local variable write before the case structure.
The attached quick modification illustrates some of the above points. This is not a finished or even reasonable program. It would need a complete rewrite.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
StateSimulatorfromEE428MOD.vi ‏64 KB

Data acquisition in a state machine

I've recently learned how to implement state machines, but I have a question that I haven't been able to find an aswer to.
Question:
How do I record uninterupted data (presently i'm using the DAQ assistant to record a single channel at 10kS/s at 1kS intervals) without interfering with my state machine?
Background:
I have a time sensitive test setup (measuring pressure in a rocket chamber), and I'm using labview to both record a single pressure transducer as well as operate the valves (O2, N2, igniter, etc). I'm using a state machine Labview architecture (just learned how). Presently, the DAQ assistant sits in the "Idle" state, and timers (valves need to be turned on at specific times) and manual buttons control when the other states are activated. I have a 10ms timer controlling how often each state is run, and this is the root of my concern.
Main concerns:
I'm worried that:
1) I'm forced to change my data recording to 10ms intervals to match the 10ms timer, and
2) The 10ms timer will interrupt my data recording when it's in another state.
It's very important that the pressure data is recorded without interruption but that I have high time resolution in controlling my valves as well.
Thoughts:
1) Maybe I put the 10ms timer in the "Idle" state only, and this way the other states won't interrupt the data acqusition
2) Maybe there is a way to completely isolate the state machine for controlling the valves and the data acqusition. I'm not sure how to do this.
3) People on the forums have been talking about Queuing their data acqusition, but I'm not sure how this would benefit my situation.
Thanks to everyone for their feedback!

The data acquisition and state machine timer do not have to be equal, you should however have the same data write rate as you have data read rate, otherwise over the course of long running programs you can build up a large buffer of data to be written using a lot of memory, or lose data.
Your data acquisition should be continuous, the most common way of doing this is every time you receive data write it to a queue, then when you are in other states except your data write stage you simply build up data in the queue that is to be written when you enter the write state again.
Think of it as traffic reaching a set of lights:
The traffic represents the data acquisition, there is a constant flow of it always coming through, the state of your state machine is the lights, green is the data write state clearing the queue, red is when in any other state, letting the traffic build up behind the lights.
It is just important that the light is green long enough to let the traffic not build up too much, otherwise you have a jam.
EDIT: For the basics of how queues work, look at the Queue basics example from the example finder.

Data acquisition & state machine

Hi all,
I am working on a project that is capable of data acquisition, analyse, and record processes. I have to acquire data of temperature from 8-32 channels and that of pressure from 7 channels. After analysis, I have 48 outputs. I want to record raw data (acquired) and analysis data at the same time.
1) Is it possible to record two text files (raw data and analysis data records) at the same time?
I also want to adjust acquired sample rate but I have doubts about utilizing it in a state machine. For now, I have just used time elapsed function to acquire data once in 60 seconds.
2) How could I set sample rate of acquisition except using time elapsed function?
I also have one more doubt about timing. If I needed to acquire sample once in 60 seconds, but the analysis took more than 60 secs, what would happen?
3) How can I prevent data loss in this case?
I have not prepared a user interface yet.
4) How can I utilize it? Do I put graphs and indicaters in the same VI or is it better to prepare another vi just for user interface?
Thanks in advance
Egemen
Attachments:
Program.llb ‏433 KB

Hi Egemen
-          If we need to acquire data and analyze it at the same time we recommend the architecture producer-consumer to prevent data loss, and yes you can record two text files at the same time. Please take a look to this architecture.
-          http://www.ni.com/white-paper/3023/en
-          Basically you use the first loop to acquire data and the second one to analyze and record data (using queues).
-          https://decibel.ni.com/content/docs/DOC-2431
-          You can also find examples about this architecture at the developer zone.
Regards

How can I keep a state machine readable when using large amounts of in/outputs

Hello, I am new to Labview,
Read trough the fundamentals and the
getting started and a lot of examples.
What I want to do is use a standard
state machine from the template, and add some stages, for example
orange, apple, banana. At this point I can use numeric controls to
put in the amount of oranges, apples, bananas there are. I can even
use a led to tell the user which state of the state-machine is
active.
The thing is there will be more numeric
controls and more leds and it would be nice if the code would still
be readable when there are 20 inputs and 20 outputs.
Questions
(1) It would be nice if I could use the
typedef to select the right state AND the corresponding numeric
controls and leds out of a cluster or an array kind of structure to
keep the number of wires low. Is this possible, how can I do this?
(2) I tried to put the numeric controls
into a cluster but that way I can't put the numeric control for the
apples in the upper right corner and the numeric control for the
oranges in the lower left down corner of the front panel.
(3) An example would be really nice, I
know that I saw some examples describing this problem but there are
so many examples that after a few hours of searching I haven't found
the right one yet.
Thanks in advance for the effort.
p.s. I will not use Labview to do
calculations on fruit, I am only using this to make the question
easier to understand.

I can only start a proper answer but I might as well start with that.
When I am developing State Machines I have to think about what data is used and manipulated in each state. I then have to think about where am i going to keep and manage the data. I list all of the fields that are "touched" in each state and what values are used together and which are independent form the others. After this phase of the analysis, I usually have some data structure defined (cluser array etc).
Then I flipp from thinking about the state to thinking about the data (after all this is LabVIEW and the data-flow paradigm is critical). If I see data that is only used by the State machine and is used in many of the states, then the data structure get put in a shift-register for easy access in each state. This maybe enough of an answer for your fruity question.
When i see data that is shared or only used in a handful of states then I concider putting the data in an Action Engine. Depending on how you design your AE, you can access each of the fruit totoal by name or increment etc as required.
If your app demands many fileds that are all related (can't be broken into distinct data structures) then create a cluster that has all of your values that are used by the AE. Then create an Wrapper VI for each call of the AE but only put the associated fields on the FP of the wrapper and then bundle that value into the cluster and invoke the AE.
Ben
PS: Sorry about reverting to neBulus mode but this topic could take days to cover in detail.
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Replacing a state machine?

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