help on field point subvi

[nw]

Hi to all, sorry for not making things clear.

I'm designing a project about field point temperature control. This is my first time doing on field point so please help me as much as possible. thank you..I found an example of field point temperature control and some of the subvi are missing, i.e. FP open, read, write, and so on. also, this project is a turn on/off fan with a relay. however, i'm using three fans and it should turn on/off at different time depending on the set of temperature,,, for example, fan1 will turn on at 25 degree C and turn off at 30 degree C,,then Fan 2 will turn on at 35 and off at 40,,, and fan 3 will do the same at 45 and off at 50 degree C,,

Can one Thermo couple do the job or should i have all Three thermo couple.

thank you in advance

[andre.buurman@carya]

I think one Thermo couple will suffice, if the fans should respond to the same temperature.

André

Message Edited by andre.buurman@carya on 09-02-2007 07:39 AM

[RDR]

Hello,

It sounds like you do not have the FieldPoint driver installed, what version of LabVIEW are you currently using?

-Bob

[nw]

thank you for responding,

I have a 8.0 labVIEW,,,, i might have missed something, can you help me about field point, thank you again

[Ching_F.]

Hello nw,

If you are using LabVIEW 8.0, you will want use FieldPoint 5.0.1.  Make sure that LabVIEW is installed before you install FieldPoint to ensure that the driver will automatically install support for the correct LabVIEW versions.  This should allow you to load the example without any missing FieldPoint VIs.

You should be able to use one thermocouple to measure the temperature even if you have three different set points.  The thermocouple will constantly measure the temperature while you use the software to set your set points.

Please let me know if you have any other questions.

[nw]

thank you again to all masters of labVIEW,

I have this question, first of all, thermo couple only reads in millivolt. how do i change that into temperature to be read by labVIEW, second i found an example of field point temperature control,,,, however, im not sure how to make labVIEW turn the Fan on and off. well here is how my project sound like.

I'm building a temperature control using thermo couple to do the measuring, because it's going into hot boiling water,,, the boiling water is my heat source, this heating is been measured by thermo couple type K, (( can i use thermistor to dip into heating water , in replacement of the thermo couple )) also, i have three actuators, or devices that going to be turn on and off  using a relay depending on the setting of the temperature. For example if my setting for the heat source rearched 60 c, then my heater will turn off. if it dropped below 60 then the heater will turn back on. this is for my 1st  temperature setting.........the second setting is the water pump and fan,,, which will be switch  on/off using a relay.  I have no clue how to get started, please share your skill and knowledge with us.

here is my plan

heater min temp on=60 celcius                         fan/pump  max temp on= 80 celcius

            max temp off= 80 celcius                                        min temp off= 60 celcius

please advise on where should i start,,,,,  here's what i wanted to us as example  pid_temperature_control.vi,,,,thank you so much for help me out

[Ching_F.]

Hello nw,

I will try to address all of your questions in an organized manner.

1.  To change the [c]FP-TC-120 readings from millivolts to degrees you will need to use Measurement and Automation Explorer (MAX). 
            A.  Find your FieldPoint controller under Remote Systems in MAX. 
            B.  Right-click on your controller and choose to Find Devices. 
            C.  Then, a dialog box will appear so you can name your FieldPoint controller. 
            D.  You can use the default name or re-name the controller yourself.  Click ok when you have named your controller.
            E.  This will display all of the devices you have connected to your controller.
            F.  Click on the [c]FP-TC-120 module and select the Channel Configuration Tab.
            G.  A Range option will appear so you can change the measured range of the module to degrees.  You can also define the thermocouple type on the Channel Configuration                       Tab.

2.  If you want to turn on and off your heater and fan based on the temperature, the example you found has the basic structure.  It will read the temperature in via the FieldPoint Read.  You can replace the pid.vi with a case structure to write different values to your relay module via the FieldPoint Write VI.

3.  I am assuming that you are using a [c]FP-TC-120.  If this is correct, you will be unable to measure the temperature via a thermistor.  The [c]FP-TC-120 is a thermocouple input module and only able to measure voltages and temperatures via thermocouples.

If you need further assistance, please provide a comprehensive list of the hardware you are using. 

Also, I would recommend looking through the FieldPoint Help which can be found at C:\Program Files\National Instruments\FieldPoint\documentation\Online Help\fplv.chm.  

Message Edited by Ching P. on 09-05-2007 10:39 PM

[nw]

Hello again,

I also have another question, my school has a labVIEW 8.2 Pro  will the field you gave me work with 8.2 version. also

what board will i be using to run my hardwares.well this is my hardware,, i have a 120 volt ac heating source

a 120 volt ac fan and a dc water pump which is about 15 volt dc, and my teacher wanted me to use a PWM to control

the pump, anyone have any idea how i will implement this  PWM into the software. thank you

see you again..oh and you guys are the best

[Ching_F.]

Hello nw,

Yes, the FieldPoint 5.0.1 driver will work with LabVIEW 82.

When I ask what hardware you will be using, I am referring to the model of the FieldPoint modules you are using.

As for how to implement code for the PWM module, I encourage you to read through the help file I pointed to you in my previous post.  The help file is not very large, but contains most, if not all, of the information you will need to get started. 

Please review the help file and ask any specific questions you may have.  It is usually beneficial to post any code that you have written and what you have already tried. 

[nw]

sorry for all the questions,

I just getting started with the plan, you talked about field point modules,   which one is low cost and capable of running my school project? thank you