Histéresis de temperatura en LabVIEW

Hola a todos.
Estoy haciendo un proyecto en el que uso una entrada que es un sensor de temperatura y tengo un problema al hacer un VI en el que haya un ciclo de histéresis que, por ejemplo, me encienda una caldera y si la temperatura supera 39,5 ºC se pare. La caldera no se volvería a encender hasta que la temperatura baje de los 36,5ºC, es decir, lo que viene siendo un ancho de histéresis. Les adjunto lo que tengo hecho para ver si me podían solucionar el problema (los estados se pueden obviar, ya que posiblemente los elimine).
¡Resuelto!
Ir a solución.
Adjuntos:
Proyecto curado de tabaco.zip ‏70 KB

Hola! Veo que ya te dierón una solución, pero me gustaria compartir otra opción de control con histeresis.
El "Histeresis negativa VI" es el control con histeresis. El Bloque CV VI es un ejemplo de como se utiliza.
SALUDOS.
Adjuntos:
Histeresis negativa VI.vi ‏17 KB
Bloque CV.vi ‏20 KB

Similar Messages

Controlador on-off con histéresis: ¿Me podéis recomendar o enviar algún .vi con un sencillo controlador de este tipo?

Hola. Se me ha dificultado encontrar un controlador on-off (ni simple ni con histéresis), y me gustaría que me orientasen para encontrarlo o -si es su buena voluntad- enviarlo por acá.
Muchas gracias.

Hola JuanCamaney
Gracias por utilizar los foros de National Instruments.
Para manejar Histéresis dentro de LabVIEw puedes utilizar la funcion In Range and in Coerce con la cual puedes saber cuándo un valor se encuentra entre determinados límites de histéresis ya que te da una salida booleana. Dicha salida la puedes conectar a una estructura de casos y ya tomar la acción pertinente. Te anexo unas ligas donde se utilizan funciones más básicas para el mismo fin, pero a final de cuentas utilizan una estructura similar a la que te comento.
http://zone.ni.com/devzone/cda/epd/p/id/311
http://forums.ni.com/ni/board/message?board.id=6170&thread.id=5160
Ahora tu generación de señales también la puedes configurar con histéresis mediante los triggers para que sólo adquiera/genere cuando se encuentre en una determinada ventana de valores, te anexo una liga donde se explica esto:
http://zone.ni.com/devzone/cda/tut/p/id/4329#toc1
Saludos
Carlos Pazos
Applications Engineer
National Instruments Mexico

1-wire temperature in LabView

Hi
I'm trying to write a driver for 1-wire (www.ibutton.com) to LabView.
For starters I didn't have any contact at all! But now I can read the uniqe ID from temperature sensors connected to both my USB and my RS232 adapter.
And then the fun stops.
I can not communicate with the temperature chips (DS1920 & DS1822) I can't even get the IsTemperatureContainer to reply with a true.
Does anyone have the time to review my code and maybe suggest changes?
You can request a free samlpe at www.ibutton.com I recomend getting a DS1920 and a DS9490B for testing purposes, order sampels from here: http://www.maxim-ic.com/samplescart.cfm
You need to have the OWAPI installed (http://db.maxim-ic.com/ibutton/example/)......
But if you know a better way or can use one of the other API's please let me know. I just need to read the temperature, how it's done is not important (except it has to be done with LabView).
Please help, this is very urgent.
J;-)

I am trying to do the same with DS18S20.
I plan on using a DS2480 to convert 1-Wire to RS232.
I need to use simple ASCII commands which I plan to write a Automated test program in LabVIEW.
Should I get HA7E is a RS232 to 1-Wire interface? or can HA2 - RS232 1-Wire Host Adapter do the same function?
I have a DS1820 I need to use the CRC algorithm Specified by Dallas and
perform the following Tests:
Read 64 bit ROM of DS18S20, Resultant byte from CRC algorithm must match
the eight (last) byte of ROM.
Read 72 bit Scratchpad of DS18S20, Resultant byte from CRC algorithm must
match the ninth (last) byte of Scratchpad.
Next, I have to:
TH byte is downloaded from E2 memory to scratchpad. TH byte in scratchpad
is read.
TL byte is downloaded from E2 memory to scratchpad. TL byte in scratchpad
is read.
Finally, I need to read Temperature, which is read via data in
bytes 0,1,6 & 7 of the Scratchpad.
Can I accomplish this by MANUALLY typing the commands over the RS-232 Comm
Port from a PC?????
If anyone has any comments or am I taking the correct path? your help appreciated.
Thanks

Monitoring Thermocouple Temperature on Labview

In our project we are trying to get different temperature values from different thermocouples connected to our NI DAQ.When we run the program we get different temperature values from .xls file but we cannot monitor this different temperature values on Labview front panel's thermometer digital display .Even we connected different thermometers we get the same temperature value in all digital displays.Could you please help us to monitor different temperature values on digital display.
Solved!
Go to Solution.

Hey tata,
I think what you are looking for is the "Split Signals" VI, shown below in the code snippet. It lets you split the data wire into each of the corresponding thermocouple data values.
I hope that this helps.
Regards,
Ryan

Mantener una temperatura en labview

Necesito hacer un programa que me mantenga una temperatura y que no pase de cierto rango tambien que cada vez que eso pase me prenda un led, mientras que se esta graficando.
espero puedan ayudarme.

There is a function in the Programming >> Comparison palette called "In Range and Coerce.vi".
You can set an upper and lower temperature bound and the LED will stay lit as long as you are within the range.
Or if you want to know every time the temperature falls outside the range, just add a Not in front of the LED.
Cory K

NI PXI 4351 read temperature

Hi,
I'm trying to read temperature from TBX-68T connected to NI PXI-4351.
I see PXI-4351 in my hardware explorer, it show me right data in test panel.
But, I can't found any tools for reading temperature in LabView!
I installed drivers for NI PXI 4351
http://joule.ni.com/nidu/cds/view/p/id/285/lang/en
but still noresults. Driver didn't contain any examples for reading.
I use LabView 10 and I have NI DAQ Traditional 7.4.4
so, I confused. How read temperature?

JaredRo wrote:
Hi kmcdevitt,
The SC Express product family was specifically designed to take advantage of the PXIe architecture and therefore the timing circuitry on the PXIe-4353 is not designed to be compatible with the PXI platform. There are no plans to design any of the SC Express products in the PXI form factor.
Jared,
Please explain what it is that makes the PXIe-4353 so special that there can not be a PXI-4353.
This 32-Channel, 24-Bit, Thermocouple Input Module does 90 S/s/ch sample rate in high-speed mode or 1 S/s/ch sample rate in high-resolution mode. Surely you are not claming the the PXI platform's architecture and timing circuitry can not hadle the troughput generated by the 32 channels of 24bit data at 90Hz.
Jared, it is not a pleasent fealing to be prommised that the new signal conditioning cards are going to be made for your soon to be purchased PXI-1045 chassises, and later find out from an Applications Engineer Jared that it has been in the plans to never make PXI versions of signal conditioning cards. How would you feel if you purchased about 30 PXI-1045 18 slot chassises with PXI Embedded RT controllers with the promiss that if you bought the controllers and chassises that NI would continue to develope new Signal Conditioning and Other PXI Cards for your chassises. Just buy them, and the new PXI cards will come. How would you feel when you were told to be patient and just wait till next years NI week. How patient would you be after the second year of being told to be patient until the next year's NI week? How patient would you be after the third year of being told to be patient until the next year's NI week? I have been recently asked to be patient again. NI Week 2012, there may be something. And now you tell me that there will never be anything.
I just don't buy it that there is something about the PXIe architecture and therefore the timing circuitry that is required for 90 Hz data.
Kevin.

Changing Colour Display for Temperature Distribution

Hi everyone,
I am currently involved in reading a series of temperatures along a length of pipe as part of an experiment. I thought it would be a nice touch for my VI to have a diagram of the pipe which changes colour to show the temperature distribution along it.
I have attached my initial solution. I would have posted a VI snippet but this seemed to effect the my references in the property nodes.
Issues
The code 'works' in the sense that the foreground colour of each tab control will change based on the value of the corresponding temperature.
The solution does not scale well. I need 'n-1' case structures for 'n' colours/temperatures. I considered using an enum input to a single case structure, but was not sure how to compare this to the for loop index.
Unsure whether changing a tab control background is the most efficient way to do this. Not sure of an alternative.
I am looking for suggestions as to how to do this more efficiently as there will be up to 16 temperatures in the final system.
Many thanks in advance,
Pete
Regards,
Peter D
Attachments:
Temperature Display.vi ‏16 KB

Tabs are probably the weirdest choice here. Why not use e.g. a simple colorbox or button?
In any case, try to learn about autoindexing, it will dramatically simplify your code (see attached in yellow box).
I probably would use an array of clusters, each containing a colorbox and a numeric with transparent background. Modify as needed. (see attached in green box).
Of course you probably would want to make it a it prettier than my draft.
For a larger ramp, I would use a plain array of flat colorboxes. Now simply index into a color ramp to generate it according to your temperatures.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
Temperature DisplayMOD.vi ‏18 KB

Débutant Labview 6.1 - Hexa / VISA

Bonjour,
je suis débutant à Labview je fais un stage dans un labo. On a le
logiciel Labview version 6.1, on l'utilise avec un photomultiplicateur.
J'essai d'améliorer linterface de notre programme, car pour l'instant
le seul moyen de faire fonctionner le programme est d'aller dans le
sous programme et de modifier manuellement la valeur hexadécimale... (
cf lab0.jpg )
J'ai essayer deux autres manières ( cf fichier joint labview.jpg) mais aucune des deux ne fonctionnent
La valeur héxadécimal doit etre un nombre de la forme 49#0D où # est le temps d'intégration compris entre 6 et 50000.
A chaque fois le programme renvoit une erreur de type -1073807339 après
le bloc Visa Redaer ( Le délai d'attente(timeout) a expiré avant que
l'opération ne soit achevée). Donc voilà je désespère un peu Est ce que quelqu'un aurait une idée?
Je pense qu'un des problèmes de la méthode avec la chaîne concaténée
vient du fait que cette chaîne n'est pas reconnu comme étant une chaîne
héxadécimale par le Visa Write, mais j'arrive pas à trouver de solution.
Merci d'avoir pris le temps de me lire, j'espère que quelqu'un pourra m'aider. Bonne soirée
Attachments:
lab0.JPG ‏13 KB
labview.JPG ‏132 KB

Hello
To get an answer on this part of forum you should post in English.
However you could post on the french forum here
This following link should be helpful : http://www.ni.com/support/labview/visa/verr2.htm
I advice to have a look here too.
Regards.
Romain D.
National Instruments France
#adMrkt{text-align: center;font-size:11px; font-weight: bold;} #adMrkt a {text-decoration: none;} #adMrkt a:hover{font-size: 9px;} #adMrkt a span{display: none;} #adMrkt a:hover span{display: block;}
NIDays 2010 : Conférence mondiale de l'instrumentation virtuelle
>>Détails et Inscription<<

Watlow F4 Controller with LabView

Hello all,
I have a HX300 circulating chiller that uses a Watlow F4 controller. I want to control the F4 controller and monitor the conditions from it such as pressure rate and temperature using LabView. I heard of the Modbus driver that helps make this communication possible and have downloaded it. I am using the LabView 8.6 version and followed the necessary steps to include it into Labview. I have very little experience with Labview and am wondering how to begin writing the code for this. Any help is very much appreciated!
Thank you,
Eric
Solved!
Go to Solution.
Attachments:
labview 86.zip ‏1900 KB

Start here:
http://www.ni.com/gettingstarted/labviewbasics/
and here:
http://www.ni.com/academic/students/learn/
and here:
http://labviewwiki.org/LabVIEW_tutorial#External_Links
And if you have an active SSP here:
http://sine.ni.com/myni/self-paced-training/app/main.xhtml
After all of that open the Examples in the code you posted and see if they work.
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.

Resistance to temperature

Hi,
I need to accept the resistance and convert that to temperature in Labview. Cn some one give me the formula.
Actualy I need to get the temperature below 73K. But my RTD (FP-RTD-122) has data configuration as 73k - 1123k and not below 73k.
So i hv to do this is the labview program by accepting the resistance (0-400 ohms) and convert to temperature.
Thanks in advance.

To clarify, this topic is a duplicate to the one linked above.
Trey B
Applications Engineering
National Instruments

How can I determine how long it take the lab view circuit to execute once?

I'm working on a temperature control labview simulation that works with an external temperature device and I have my labview stimulation set up so that I can turn a external light on or off (which is in a chamber) and the temperature is measured inside that chamber and I displayed versus time in the labview x-y graph. I can internally turn the heat source (the light) on or off and see the waveform change. Now the information that is being displayed on the waveform is also being saved to a data file. And I noticed that as soon as I run the stimulation of the circuit on the first input into the labview while loop is from the data file. now the first execution of the simulation will start as soon as the data files sends an input into the while loop and the second execution of the labview loop will happen the next time the data file inputs something into the while loop of labview. Now, by using circuitry inside the while loop, how can I record the actual time of the initial input (into the while loop) along with the time of the second input into the loop so that I can determine how long it take for one execution in labview will take.

One thing to keep in mind about the Tick Count VI. It uses the ms clock from the CPU which rolls over back to zero after it reaches an upper limit. You might end up getting very large negative values if you subtract the current value from the last value.
Once every 39 (?) days that can happen but are you sure abou the large negative thing?
I seem to remember Rolf saying that the math takes care of itself. A quick experiment confirms that memory.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Changing time to the number of cycle

Dear Friends,
I will appreciate if anyone helps me.
I am trying to convert time to no. of cycle in my program. Actually I am reading temperature from externel device. I put my program in a loop and I can see temperature chart which varies with time. how can I get a out put of time from wavechart output and calculate it to no. of cycle?
I know the frequency of my external device which sends temperature to labview.
Regards,
Mehdi
Attachments:
Panel.JPG ‏178 KB
front panel.JPG ‏193 KB

In general, if you know the time the first sample was taken and the time between samples, a little simple math will tell you the time each sample was taken:
time_for_sample_n = start_time + (time_between_samples * n)
Given this, you can easily calculate an array of times for each sample, that you can then use for the x-axis of a graph.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

Eurotherm 2704 connection via serial port with ModBus

Hello guys,
first some words about my problem:
I have to develop a software which allows reading and writing the
temperature (we have 3 Eurotherm 2704) (I think some of you know this problem yet ).
I wrote already the program and it works, but I used "iTools OPC
Server" for my program and it was the demo version (works only 30 minutes).
The group doesn't want to pay for the iTools, I should solve this problem without
iTools .
In this forum I found out, that I can use the ModBus for it:
http://forums.ni.com/ni/board/message?board.id=170&thread.id=468139&view=by_date_ascending&page=2
I know, there are some similar threads here, but I am new with LabView
and need some help.
I downloaded one example “my modbus serial query.vi “
http://forums.ni.com/ni/board/message?board.id=170&thread.id=135288&view=by_date_ascending&page=2
but it does not work (I am not really sure, what I have to change in the
file)
With OPC Server I found out:
COM5
Baud Rate 9600
Parity: None
Flow Control: None
Data Bits: 8(RTU) (I can choose RTU, but where can I change to 8 bit ?! )
And by other properties, I have no idea what I have to change there
For Example
Modbus Data Unit In (all read and write mode ? Which one do I need to read the temperature and to set the set temperature?)
Modbus Command ?!!!
No idea.
I have folowing adresses (comms address 0x00030001, canonical address: 1)
Which one do I need ?!
I think if I get the signal from one temperature controller, I can do it for
other, but my problem is now THIS one.
Can you help me whit it ?
Should I use a other example ?! Maybe do you know better one?
Thank you, very much.
Alexander

Hello Putnam and Christian,
I think the problem because you can not understand my question is my English, sorry
I'll try it again:
@Christian:
Thank you for the links, but I think all threads in NI Forum with topic "Help, Eurotherm 2704 ?" were written by me
You understood my problem correctly.
We have 3 temperature controllers and I have to develop a LabView program, which allows reading the temperature from the controllers. It should be possible to write the set temperature from LabView to temperature controller as well.
The controllers are connected already (I think with RS485) and I can read/set the data from/to controllers (with “iTools OPC Server”), but I have to change my program so, that it works without “OPC Server”
@Putnam:
In the meantime I found out, why I got an error with “my modbus serial query.vi” (the solution was very simple, I had to close the OPC-Server ).
It runs now and I try to understand now how the VI exactly works.
Maybe you can help me with it?
I try to explain what I understood, if something is wrong, tell my please:
The “my modbus serial query.vi” allows to read the multiple values (maximum 125 register) (default block read size is 125) from controller (I can see the data in the register array). In each register I have values for different variables. The Modbus address of Loop1 PV (I need this value) is known ( 00001, Eurotherm manual).
Does it mean that the first element in the register-array is the value for the temperature from Loop 1 ?! (multiplicated by a factor, if it is correct, how can I find out this factor? It is linear?)
And if I need the value of Loop2 (the address is 01025), I have to set the start address for example to 1000 and in this case the 25-th element in register-array is the value for PV Loop 2 ?!
I got this idea, after I left the laboratory and could not try it out. I can do it first at Monday, but I would know if it is correct what I think.
If it is correct, I think I will able to change “my modbus serial query.vi” on my own, that it works in my program.
Or there is a better example/solution than “my modbus serial query.vi” ?!
The other problem would be writing of temperature, but I will ask about it later . First temperature READING problem!!
Thank you!
Alexander.
Message Edited by alexphysiker on 01-29-2010 05:30 PM

Bad temp readings when sc2345 connetor fully inserted into chasis

I get bad temp readings when daq cable is fully inserted into "New" SC2345 chassis in LabVIEW, but in NImax numbers apear to be good. When cable is partialy inserted numbers seem to be ok all around. I have tried an identicale cable and dac card (DAQCard-6062E) on same laptop and got same error. If i hook up to an older SC2345 chasis the problem is not there. I have also hooked up a PC with a PCI-MIO-16E-4 daq card and the appropriate cable for this card and have no problems on the "New" SC2345.

OLD EQ PC
NEW EQ PC
OLD EQ LT
NEW EQ LT
TEMP
81.6
87.7
81.2
86.8
TEMP V
-0.000049
-0.000320
-0.000049
-0.000322
CJC TEMP
83.5
101.7
83.7
101.9
CJC V
1.093750
0.847500
1.093750
0.846100
Temp LV
81.6
87.6
64.7
36.5
REF TEMP
82.6
82.6
82.3
82.0
Temp (Temperature in max), Temp V (Temperature voltage in max), CJC Temp (CJC temperature in max), CJC V (CJC Voltage in max), Temp LV (Temperature in LabVIEW application)
Refrence temp was with an Omega Hand held unit.
Old EQ PC (Old SC2345 chasis with PCI-MIO-16E-4 Daq card and P/N 184749C-10 (10 meter cable) PC)
New EQ PC (New SC2345 chasis with PCI-MIO-16E-4 Daq card and P/N 184749C-10 (10 meter cable) PC)
Old EQ LT (Old SC2345 chasis with DAQCard-6062E Daq card and P/N 192061B-02 (2 meter cable) Lap Top)
New EQ LT (New SC2345 chasis with DAQCard-6062E Daq card and P/N 192061B-02 (2 meter cable) Lap Top)
There are no bent pins on any of the componets.
The LabVIEW application and daq settings are identicle.
The same CJC Map was used for all test.
Thanks in advance for any help you can give.
Travis

NI 9213

I am trying to plug in a thermocouple into N-9213 and see if i can get measurments of temperature. I am very new to LabVIEW.. i am trying to see if i can get the temperatures in LABview Express ...
it gives the following error. I am not sure if i am doing the write thing. Can anyone help me how to go about this..
Error -88302 occurred at DAQ Assistant
Possible Reason(s): An internal error occurred. --------------------
Error -200486 occurred at DAQ Assistant
Possible Reason(s): Measurements: Specified channel is not in the task. Channel Name: cDAQ1Mod4_ai0

Hey Shanky,
One reason you might be getting that error could be due to not having that channel name in Measurement and Automation Explorer. You'll want to check to make sure that cDAQ1Mod4 is the 9213 you're trying to reference. As well, you may want to reference this post and this post, which describes a similar error. It could simply be that there's something wrong with MAX. Let me know if either of those solutions doesn't work!
aNItaB
Applications Engineer
National Instruments
Digital Multimeters

Histéresis de temperatura en LabVIEW

Similar Messages

Maybe you are looking for