Thermocouple reading (w/ Built-in CJC Source) only works on random SCB channels

I am using LabVIEW 8.2.1, a PCI-6255 card, and an SCB-68 terminal block. I have a Type K thermocouple with a thermocouple calibrator which I am trying to measure. Here is the problem, first, using the attached VI, I have tried to read this TC using AI0. Everytime I use AI0 I get the error saying Built-In CJC is not available. When I use any other channel, this error disappears. The second problem, when I use a channel other than AI0, I am only able to successfully read the TC on random channels. For example, it only works on AI13 to AI15. For the channels that it does NOT work on, I am able to see the correct voltage through MAX, however the AI Read TC VI does not for some reason give an accurate reading.
Does anyone know why I would not be able to use AI0, and why I am only to use certain channels for this TC? This makes absolutley no sense and I have tried swapping the SCB, the DAC Card, and the cables. I have reinstalled drivers and LabVIEW also.
Please help this is driving me crazy!
Thanks
Solved!
Go to Solution.
Attachments:
test.vi ‏28 KB

bkb wrote:
So AI0 is the CJC value? And I have to specify CJC Channel when I read the TC? Why is it that I got this to work when specifying Built-In source, and wired the thermocouple to AI15? And why does it not work on other channels?
Not sure if this helps you but...
Thermocouple reading are often differential measurements since they are typically very small values. To get differential readings two AI channels are paired up so half of the channels go away when you set things up for differential measurements. So could you double check the documentation for your device to ensure you are wiring the thermocoules properly? Correct pair, proper polarity, and proper TC type specified.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Similar Messages

Macbook air built-in keyboard/trackpad only work at login screen

The built-in keyboard and trackpad have become unresponsive on my 2013 refurbished macbook air. When I restart it, everything works normally at the login screen, but becomes unresponsive again once I've logged in. The computer works fine with external inputs or a shared screen.
I've recently updated to yosemite. The fact that everything works up until login makes me think this is a software problem. I've tried all the troubleshooting steps listed here, and I've reset PRAM and SMC. Does anyone know what could be causing this?

Hi,
I was able to get result from apple store after 24 days not hours days. They said it's my fault and they have found liquid inside of it and when i asked to see pictures of it they asked for COURT ORDER and repair will be cost around 400$.
I am %100 sure that my macbook air never touched with liquids.
I was using it for business and not even fluids there isn't any one scratch on it. I have been very careful.
Did they asked 400$ for you too ?
I am also using mac mini and iphone 5s. I think i will never buy an apple again.
And i will definetly go to court.
Repair R146244431

Does built-in cjc supported by daqmx 7.4?

Hello!
I am using pci6251 and 6221 with bnc2120 accessory with built-in cold junction compensation enabled in MAX device properties.
Some time ago we have used DAQmx 7.3 and everything was fine. After upgrade to DAQmx 7.4 in MAX it is possible to select built-in cjc source, but trying test the task results in error like: "property value unsupported", supported only "channel" and "constant".
Is that intended behaviour? If so, why the built-in is in the list of the possible values in MAX?
I understand that it is easy to setup a new channel for CJC only (with voltage*100 degrees C linear scale), but is it possble to use just builtin value of the CJC source with this driver release?
Thanks in advance!

Hi,
Roughly speaking, CJC channel should contain the temperature of the place where thermocouple wires are connected to copper. Various way exist to do it. NI uses the semiconductor temperature sensor which voltage output is 10 mV/oC (it is practically standard among such sensors). (It is very easy and cheap to by yourself such thing if you don't have).
So, you need two channels - one for measuring the thermocouple voltage and second for the sensor output. Then you need to convert both to degrees C and sum them (i.e. sum the thermocouple temperature referenced to cold junction temperature and cold junction temperature itself).
Create one channel on which you will measure temperature of cold junction, add scale to it (offset=0, scale=100) to have results in oC.
Create second channel on which the thermocouple will be connected (sure that it is another channel than CJC :-). Specify the first channel name in the "CJC Channel". It should work.
If your are using the BNC2120 with builtin junction compensation sensor and thermocouple connector, be sure to set the corresponding switches to measure temperature and CJC on the block instead of the BNC.
Hope this will help.
If not, try to search through NI website. There are some appnotes or knowledge base articles describing CJC and thermocouples in details.

Built-in microphone only works when phone is connected to iPod nano cable

Hi, I got an iPhone yesterday but the microphone doesn't work properly. I have figured out that the built-in microphone will only work when I connect the dock cable from a second generation iPod nano. The cable that comes with the iPhone does not work. The supplied handsfree earbuds work correctly at all times.
The strangest part of the problem is that the iPod dock cable doesn't have to be connected to my computer!
I'll state the problem again. Let's say I make a phone call. The person on the other end cannot hear anything I say, but I can hear them. Then I plug in the dock cable from a second generation iPod nano, and the other person can then hear me. Unplug the cable and they can not hear me.
I have tried restoring the iPhone three times, turned it on and off, and inserted and removed the headphone plug many times. These actions do nothing. *The only way I can talk on my phone is if I insert the dock connector from my old iPod!*

Take it back.....

Difficulty with CJC using on board temp sensor - SCB-68

I am trying to do Cold Junction Compensation using the built in temperature sensor on my SCB-68 connector block. I am using the 6224 M Series PCI DAQ card. I am having two problems:
1. I found a procedure on this forum for reading the temperature sensor which, in my case, is at channel 16. So, I have my connector block switches set so the Temp sensor is enabled, and I am in differential mode. I created a global channel called "TempSensor" and set it to channel 16. I applied a scaling of m = 180 and b = 32 to get farenheit. When I do this, and I test the channel, it reads a temperature of 75 degrees. This seems a little hot for my office, which is probably more like 68 degrees. Any idea what might be wrong? I don't have to connect anything to the board to read the temp sensor, do I?
2. I've connected a type T thermocouple to channels 20 and 28 (differential). For CJC, I can set it manually by estimating the temperature in my office as 68 degrees and puting that value in the CJC Source Constant field. When I do this, the TC seems to work great. It reads around 68 degrees in my office, and more like 85 if I squeeze it between my hands. So, now I want to use the "TempSensor" global channel to do my cold junction compensation automatically. When I select my CJC Source as "Channel" and enter "TempSensor," I run the test and get temperatures of 176 degees F. What am I doing wrong?
Thanks for any help!
Kevin

Dear Kevin,
There is a really easy way to test your thermocouple using the Built-In CJC of the SCB-68. The only time I set up a global channel for the CJC is to make sure that it is working correctly. The CJC temp does not indicate the temperature of your office, it indicates the temperature of the SCB-68 board. My CJC value is 2 degrees warmer than the room temperature. 75 degrees is a reasonable temperature to get.
After you check the CJC to make sure that it is working, you can set up the task in the Measurement and Automation Explorer (MAX). Expand Devices and Interfaces>>NI-DAQmx Devices. Right click on your device and select Properties. Click on the Accessory Tab and add the SCB-68 to the second connector and click Configure. Check the box for Reference Temperature Enabled. Click the two OKs to save your changes. Then create your thermocouple task normally and select your CJC source as Built-In.
Now, it will detect temperature changes that you add. Please let me know if you have any questions. Have a great day!
Sincerely,
Marni S.

How do I take a thermocouple reading with a pci6025E?

How do I take a thermocouple reading with a pci6025E? I have seen some postings with scxi-1112 modules which I do not have. I need advice from the ground up. Do I need external circuitry, can I just wire both leads of the thermocouple to Ain0 differential pins, what vis are necessary in the actual programming... If there is an example program or anything else that might seem relavent? I appreciate any help.

This is most probably a result of multiple factor that make the measurement imperfect:
- You're not using signal conditioning, so your resolution is definitely very reduced. Any temperature drift in the board could cause a big difference in the reading. I recommend you run your vi for approximately half an hour, unplug the accessory and perform a self calibration. This will have the board at the operational temperature you're expecting and will give you the best results.
-I personally would recommend using a different sensor type (RTD or Thermistor) as the CJC source, in order to obtain an accurate measurement, otherwise you have a bit of a "chicken and egg" problem, because you're using thermocouple 2 as the CJC for thermocouple 1, but what are you using as the CJC source of thermocouple 2?
- Are both your thermocouples of the same type and manufacturer? Due to the nature of the thermocouple itself, you can find slight variations between thermocouples from different vendors, due to the purity of the metals used. While this would usually be almost impossible to detect, it might be driving your voltage just enough to be in the next detectable voltage step (again, due to the reduced resolution).
- I've worked with temperature sensors for a while, and I'd still recommend that you try some sort of signal conditioning in order to increase your accuracy. Even a small amplifier and a passive lowpass filter will do great. I know you said you don't have SCXI, but if you want some lower cost ready to use applications you might consider looking at the SCC Carriers and modules we have.
I hope these suggestions help. Please let me know if you have any other questions.
Daniel

I'm using GarageBand 10.0.1. Do the built-in drum tracks only come in mono format, or is it possible to make them true stereo (i.e. Left and Right channels outputing different signals, to sound like the kit has been panned across the stereo field)?

I'm using GarageBand 10.0.1. Do the built-in drum tracks only come in mono format, or is it possible to make them true stereo (i.e. Left and Right channels putting out different signals, to sound like the kit has been panned across the stereo field)?

All the Drum Kits available for GarageBand are mixed in stereo.
Logic provides the same 18 Drum Kits also as "Producer Kits", which are multi-track outputs,. Each Drum Kit Piece (Kick, Snare, HH, etc) and also room mice and overheads are routed to individual channel strips.
Here is a screenshot of one Drum Kit in Logic Pro X with individual Channels Strips. Each Channel Strip can be loaded with individual effects (compressor) and adduced with individual sends, etc.
What that means is that all the Drummers are professionally recorded and sampled with individual mics. The Stereo Drums Kits are just "stereo mix-downs" for easier handling and less CPU demand. I explain all the details about the Drummer ecosystem in my graphically enhanced manual "GarageBand X - How it Works"
Hope that helps
Edgar Rothermich
http://DingDingMusic.com/Manuals/
'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

Why is the thermocouple reading wrong?

Situation:
I have the PCI-6221 interface board with an TBX-68 connector block directly connected with T-Type thermocouples. Thus the temperature reading should only be between 0 and 400°C. I made a program to read 6 thermocouple channels.
Problem:
I only connected the first two channels. These are reading properly but the others give me signals which are completely nonsense! Like 600°C and so on. Do I need to install an condensator (like 10µF) at the conector block between the thermocouple contacts? How can I get a constant 0°C out of not contacted thermocouple channels?
Greets
Attachments:
Thermocouples reader1.jpg ‏203 KB

The nonsense it because of the open terminals, and the bias currents off the inputs.
If you shortcut the inputs you should read the board/cold junction/room temperature.
Or wire a 1M from AI+ to 5V and another from AI- to GND (diff mode assumed). That would give a max/overrange reading, but might have some influence to the other channels due to crosstalk but worth a try.
The clean way is to disable the readings by software.
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

I have adobe illustrator CS5. When I save a document as a pdf and open it again later to edit Adobe reader can't read the whole document because it only shows part of the document. It is very frustrating. How can I fix this?

I have adobe illustrator CS5. When I save a document as a pdf and open it again later to edit Adobe reader can't read the whole document because it only shows part of the document. It is very frustrating. How can I fix this?

keokipineapples schrieb:
I do have all of my files I am working on located on an external drive. I plan to transfer them directly to the hard drive
Transfer them to your harddisk immediately.
External drives are not offiially supported and the source of errors of all kinds including complete loss of files.
Illustrator support for networks and removable media

Tracing OSA data automatically when thermocouple reading stabilized

Hello,
        I am working on a temperature application. I have two parallely working VIs. One is for tracing data from an Optical Spectrum analyzer and the other is for monitoring thermocouple reading. I combined these two and made a VI that records the Optical Spectrum Analyzer data when the thermocouple reading stabilized.
        The problem is the code requires user feedback. I mean the VI ask the user whether to trace the data or not. I want the process to be automated completely so that I can leave the set up overnight. I want computer to record the OSA data everytime to a different column of .csv file. And since the wavelength column will always be the same, the computer can only record the power data.
Thanks
Attachments:
code.zip ‏146 KB

   By saying user input, I mean specifying the location of file. In the code 3650.VI, when temperature condition is met, a dialog appears and asks me whether or not to trace the data in a trace.csv file and asks for a file location. I want a stationary file and write all the OSA data,only power column, to be written into that file.Every time to a different column,of course.
Attachments:
trace.JPG ‏248 KB
write trace to file.JPG ‏85 KB

Thermocouple reading

Hi,
I am working with a type K thermocouple and I use a LM 35 temperature sensor to get an accurate CJC. I have got an external serial device were I do the voltage measurement of both (K and LM35), that means I get the voltage value as string using VISA in Labview.
I would like to use the thermocouple reading vi for the linearization. My questions are:
Which option should I choose on the CJC sensor input of the thermocouple reading vi?
Can I connect the value that I get from the lm 35 to the CJC voltage input of the thermocouple vi?
Thanks

Hi Navarro,
thank you for your answer.
The first thing you have to define, is the Temperature Unit you want to get as the output of the Converter VI. Please refer to the LabVIEW help for the options:
Convert Thermocouple Reading VI - LabVIEW 2014 Help - National Instruments
http://zone.ni.com/reference/en-XX/help/371361L-01/lvinstio/conv_thermcoup_read/
As you described, your serial device returns scalar singular values to you, choose the scalar option of the converter VI.
The CJC options depend on your reference sensor. You can use a voltage or current reference, depending on what signal comes from the reference. Please refer to the help and the following link for more information:
What is CJC and Why Does My Data Acquisition Board or Signal Conditioning Unit Include a CJC Sensor? - National Instruments
http://digital.ni.com/public.nsf/allkb/E332E1D829059FB5862570AE005066B3
I hope, this helps.
Best regards,
Melanie

DAQ signal accessory and thermocouple reading fluctuations

I have a DAQ signal accessory connected to a laptop via a 6024E DAQ card. I am attempting to connect a type K thermocouple to the thermocouple port on the signal accessory and take temperature readings. The VI that I have set up is a slightly modified 'continuous thermocouple reading' example VI. I am having problems getting accurate readings. The temperature fluctuates 30-40 degrees between readings. This is impossible do to the lack of thermal variations in the environment. Please help!

Nah. I think we've isolated the problems.
It sounds like noisy inputs to the DAQ board.
As I said, TCs are very prone to noise on the line, and normally there's a filter on the TC to eliminate the noise, and just get the DC component of the TC--but you don't have that.
Therefore, to get the same effect, you're going to have to average many readings, which will in effect average out the AC component.
Another thing--if your panel (TC junction) is in a controlled environment (same temperature all the time), I would average the CJC IC voltage, and just continuously use that, rather than reading it every iteration.
Try something like this attached file.
Mark
Attachments:
Continuous_Thermocouple_Measurement_Mod.vi ‏61 KB

Build Solaris 8 from source only?

I just downloaded the source for Solaris 8 and wanted to build the system from it, only it appears I need the Operating Environment to perform this and the OE is no longer available for download. Is there anyway to build the system with the source alone?

Yuechen wrote:
Hi
I understand that my requirement is kinda weird. However, I really wonder whether it is possible sometimes.
I have built ssh successfully both on solaris 8 and solaris 10. Now the problem is the binary built on solaris 8 can work on solaris 10, but the binary built on solaris 10 can not work on solaris 8.That is expected. Binaries should have forward compatibility and run on later versions of the OS.
Build on 8, run on 8 through 10.
Darren

FCP error message: Unable to read the data on your source tape!

Hey,
So I have been editing on the MacPro now for over a year and I have never seen this message before...the message reads:
_*"Capture encountered a problem reading the data on your source tape. This could be due to a problem with the tape."*_
Has anyone got this message and could help me out please? I need to edit these tapes A.S.A.P.
Thank You,
Erick

why would it start a month later giving me problems instead of when it was updated?
That is a good point. Anything change since the time it worked to when it didn't? How about trying another firewire cable. Those can go south without notice, might cause this.
Shane

Reading the data from XML Source

Hi
i want to read the data from XML source file, and update the transaction information to another XML file. how we can do this in ADF, please help
Thanks
nidhi

you may use normal Java API to do that
http://www.javablogging.com/read-and-write-xml/

Thermocouple reading (w/ Built-in CJC Source) only works on random SCB channels

Similar Messages

Maybe you are looking for