fieldpoint config and functions

[kunal227]

hi,

  i connected a fp tc 120 i/o module and fp1000 network module.

successfully configured but where to save the configuration file?

i cannot see any fieldpoint read, write, etc functions in the block diagram of labview version 8.2.  from where do i get those functions and where to save them?

[Ching_F.]

Hi kunal227,

You will want to save your configuration file somewhere you can easily find so if you want to load this specific .iak file again, you can do so.

You should be able to find the FieldPoint VI's in LabVIEW 8.2 under the Measurement I/O palette.  On that palette, you will find the FieldPoint palette.  If you do not have this, it could be that you have the wrong version of FieldPoint installed on your computer, or you do not have support for LabVIEW 8.2 installed.

To verify that you have the correct version of FieldPoint installed, open Measurement and Automation Explorer, expand the Software tab under My System, and select FieldPoint.  The window on the right will display the version of the driver.  For FieldPoint to work, you need to have FieldPoint version 5.0 or later installed.

If you have verified that you have FieldPoint 5.0 or later installed on your machine, but still cannot see the FieldPoint VI's in LabVIEW, you will need to verify that you have installed support for LabVIEW 8.2.  To check this, go to Add or Remove Programs in the Control Panel, select National Instruments Software, click the Change/Remove button, this will bring up a National Instruments Software window, select NI FieldPoint, and click the Modify button.  Now, you will see what FieldPoint features you have installed.  Make sure that the box next to LabVIEW 8.2 has an image of a hard drive and not an X.  If the box next to LabVIEW 8.2 has an X, click on the box and select Install this Feature.

Please let me know if you have any further questions by replying to this post.

Message Edited by cphuong on 05-31-2007 09:49 AM

[kunal227]

---

thanks. i was using fieldpoint 4 before this.

[kunal227]

hi

  i configured the fp-tc-120 and connected one t-type thermocouple to the channel no. 1

but the voltage value does not match the value give in the nist its database for a t-type thermocouple. it is not even near. or may be i misinterpreting.

the manual for fp-tc-120 says that it automatically compensates for cold junction temperature. please let me know if i still need to take care of the cold junction compensation or not.

i am attaching this screenshot of the channel being monitored in MAX.

[kunal227]

---

do i have to connect anything to the "C" terminal on the fp-tc-120?

[Ching_F.]

Hi kunal,

You do not need to connect anything to the "C" terminal of the FP-TC-120.

Please check that you do not have any loose connections.  That is the most likely cause of the measurement railing. 

If you would like to modify the measurement range so that it shows temperature instead of voltage, select your FP-TC-120 module from Remote Systems, select the Channel
Configuration Tab, and Change the range.

Please let me know if you have any additional questions.

Message Edited by cphuong on 06-01-2007 09:41 AM

[kunal227]

---

first:----          the remote systems  "+" does not expand
second:---     i am using FP-TC-120 and not cFP-TC-120.


Do i have to mention somewhere in the configuration what type of thermocouple i am using? i am using the copper -constantan t-type thermocouple.

[Ching_F.]

Hi kunal227,

If the Remote Systems tab does not expand, you are probably connected to your device through a serial cable.  If this is the case, you will follow a similar procedure.  Expand the Devices and Interfaces tab under My System, and then expand the FP@COM1 tab.  The next step is to expand the Bank you are using.  From there, you should be able to see you FP-TC-120.  Click on that, and should be able to define
your temperature range and your thermocouple type.

The configuration for the FP-TC-120 will be the same as the configuration for the cFP-TC-120.  I was just using the cFP-TC-120 as an example because it was already connected to my PC.  I apologize if this caused any confusion.

Message Edited by cphuong on 06-01-2007 04:21 PM

[kunal227]

thanks again for the help.

what option do i select for the cold junction temperature:   internal, 0 or 25.?

shouldn't the thermocouple show me the room temperature which is equal to the cold junction temperature when it is left loose that is the thermocouple is not inserted for any measurement? see image "config_2"

will enabling the scaling option help? see image "config_3"

[M_B1]

Hi Kunal227,

You should be able to select internal for your cold junction temperature.  The thermocouple and the cold junction temperature are not always equal, and being .8 degrees apart is not horrible.  It depends on both the specs for the Module and terminal base.  If you are concerned if your CJC is correct or not you can take these steps to check:

1. Using a DMM, measure the resistance between pins B34 and B35 on the terminal base. (See figure 1, below.) These pins are the two right-most pins on the center row when the terminals are towards you. If you are using compact FieldPoint, this measurement can be made within the CB-3 terminal block. Figure 2, below, shows the location of the "C1" contacts where the thermistor's resistance can be measured..
   
2. At the same time, measure the temperature of the heat sink (the metal bar across the top of the screws) on the terminal base (TB-3). You should be using a TB-3 for its isothermal design, but if not you would have to measure air temperature (which would be less accurate).
   
3. Convert the resistance to a temperature using a conversion table for a negative temperature coefficient (NTC) thermistor with 5k Ohm @ 25 C, +/- 0.2 C. There is a conversion table attached to KB 2SCBTB2P linked below. You can also find a conversion table at several of the vendors web sites also listed in that Knowledge Base. The CJC sensor should be within +/- 0.5 C.
   

When doing temperature measurements the TB-3 terminal base is always recommended since it is designed to be isothermal.  Also here is a great link to improve the accuracy of FP-TC-120.  You can use the scaling option if you like as long as you know what the scaling should be for your thermocouple.