FP-1000, FP-AI-110 Transducer Connection Help

[BR549]

Hello,

I am trying to connect a Omega Model: LC203-200 transducer ( http://www.omegadyne.com/pdf/lc203.pdf ) to a FP-1000/FP-AI-110.

I am using a Omega power supply Model: PSS-10 ( http://www.omega.com/Pressure/pdf/PSS-5A.pdf ) Single output barrier strip style power supply with +10 V output voltage, 400 mA output current. To power the transducer.

I am trying to connect the transducer to channel 1 of the FP-AI-110. http://www.ni.com/pdf/manuals/373280b.pdf

I have the transducer RED+ input to the +10v and the BK- input to the 10v COMN of the power supply. I am not sure where I should connect the drain wire? (transducer wires: RED+, BK-, GN+, WT- & braided drain wire.)

Should I connect...

GN+ to Vsup 19 and WT- to Iin 4 of the FP-AI-110 for channel one?

Any help would be appreciated.

[RavensFan]

You would want Green to Vin and White to Com.  Then you can read the voltage across the bridge.

But a better alternative would be to use a cFP-SG-140.  This is a module designed to measure strain gage bridges.  You would not need the PSS-10 power supply in this instance.

You can connect the drain wire at one end or the other to Ground.

[BR549]

Ravens Fan,

Can I view what the current load is on the transducer using the fieldpoint software or do I have to use Labview?

[RavensFan]

Yes, you can look at the individual channel values using MAX.  Find the remote system.  Find devices on the system.  Then you can see the channels under Data Neighborhood at the top of the screen.

[BR549]

Ok, I have another question(s).

(1) I am not sure which terminals to use to connect a "K" Type thermocouple wire. + to V-in and - to COM ?

(2) I am a little confused on the instruction you gave me on connecting the load cell, being that I am using an external power supply. Reference Figure 5. of the manual.

(3) When I open MAX, Data Neighborhood and click add new, I am only able to add a new virtual device. Is this correct or should the devices connected appear?

Thanks for the help Ravens Fan!

[JeffOverton]

Instead of Data Neighborhood, expand Remote Systems to find your connected hardware, then Find New Devices

[RavensFan]

---

BR549 wrote:

Ok, I have another question(s).

(1) I am not sure which terminals to use to connect a "K" Type thermocouple wire. + to V-in and - to COM ?

(2) I am a little confused on the instruction you gave me on connecting the load cell, being that I am using an external power supply. Reference Figure 5. of the manual.

(3) When I open MAX, Data Neighborhood and click add new, I am only able to add a new virtual device. Is this correct or should the devices connected appear?

Thanks for the help Ravens Fan!

---

1.   For Type K.  the yellow wire is positive, the red wire is negative.  Are you using the analog input module for this or a thermocouple module?  Thermocouples have very low mV voltages that  you are trying to measure that the thermocouple modules have built-in signal conditioning for.  You may run into noisy measurements if you try to use an ordinary analog input module.

2.   For external excitation, the red wire goes to the power source positive, the black wire goes to the power source negative (aka E+ and E-).  The green wire goes to Vin (the positive measurement terminal and the white wire goes to Common.  The external power supply shown in figure 5 is not the same as PSS-10 power supply, because it would share the common with the common used for measuring across the bridge, you would be effectively short circuiting one leg of the bridge and I don't think you would get good measurements.  I'm not sure that you wouldn't have problems if you used the PSS-10 to power multiple strain gage bridges and try to measure them with different channels.  It's possible you could have shared return paths for that corner of the bridges.  I've seen this problem with analog current loops that were not properly isolated.  If you have problems, I would recommend looking at a strain gage module.

3.  Jeff gave you a little more detailed explanation than I gave before.  You need to find the remote system by opening the bottom Remote Systems part of the tree.  Once  you find the fieldpoint, then you select find devices.  This will make all the modules appear at the top of the tree under Data Neighborhood.

[BR549]

"3.  Jeff gave you a little more detailed explanation than I gave before.  You need to find the remote system by opening the bottom Remote Systems part of the tree.  Once  you find the fieldpoint, then you select find devices.  This will make all the modules appear at the top of the tree under Data Neighborhood."

I assume that we are talking about doing this in MAX? Where in MAX is the "remote systems" part of the tree? Every time I add a new device to Data Neighborhood it reads Invalid Configuration when I try and test the load cell.

Also, should the range in FieldPoint for the transducer I am using be set to "0 to 10.4 volts"? 10 volts would be the input for the transducer, but the output is 2 mV/V.

Thanks!

[RavensFan]

Yes. In MAX.  See Attached

1.  Open Remote Systems.
2.  Select remote system, pick Find Devices.
3.  Look at what was added to Data Neigborhood.
4.  Pick a module.
5.  Hit Start to see the current data.

I myself would use a strain gage module in your application, I haven't tried setting up an ordinary analog input module to read a strain gage bridge.  I would set a range that meets or slightly exceeds +/- 20mV since you have a 2mV/V signal with a 10 V source.

Message Edited by Ravens Fan on 03-25-2008 02:58 PM

[BR549]

Remote Systems does not appear anywhere in my tree. I have expanded all categories, it's not there. What now?

Thanks!