Random Differential Voltage Drop (DAQ 6008)

While measuring a constant voltage of 5V with the DAQ-6008 I get voltage drops (from 5V to near 0) randomly and for very short periods of time. I've found the same issue even when using different voltage sources. I am attempting to use the voltage on this particular channel as an analog trigger. So, as you can infer, the random voltage drops cause unnecessary triggering. Any Ideas?
Regards

Thank you for your response.
I am including all of the requested information:
1. The LabView vi
2. .txt data output file (open in notepad)
3. A picture of an example setup I am using to test the triggering system (note, this is one of several setups that all have the same triggering issue)
I'm certain the connections are not the problem considering the simplicity of the test circuit as shown in the attached image.
I have my DAQ-6008's ai3 port hooked up to the voltage input (the battery pack as shown in the picture, E.G.). Normally, the ai3 port would be connected to a binary sensor that ouputs either a 5v output or a 0v output depending on the presence of an object. As you can see in the vi, I am attempting to compare each of the incoming ai3 voltages to a value (4.5); if the incoming voltage rises from 0V to above 4.5V, a true signal is outputted and the trigger should activate once by incrementing the wheel count once. The problem presents itself here by incrementing the wheel count randomly even if a constant voltage source remains above the 4.5 threshold value. You can see in the data file that all of the values are 5.208543. Again, this constant voltage is exemplified by the battery pack in the picture. There is no random incrementing if the voltage source remains at 0V.
Attachments:
ME481 DAQ WORK 10.vi ‏110 KB
IMG_20111128_131137.jpg ‏777 KB
test_11-11-28_1300.txt ‏694 KB

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My daq 6008 wil not drop the 5V after the VI is stopped, i have a digital signal going from the error out on the daq in the while loop to the error in on the daq outside the while loop and a boolean going to the data of the daq outside

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Reading Voltage Drops Across Multiple Resistors

HI,
We are creating a PC interfaced IC tester. To do this we need to be able to monitor and record the behavior of the chip in question. The easiest way we have come up with to do this is to place common resistors on the inputs and outputs of these basic devices. By doing this we will be able to read the voltage drop across each resistor, since we know the resistance we can then figure out the current, we measured the voltage and we know all we need to. The problem we are having is reading in multiple channels of data at once. We are using Labview version 7.0 and DAQ PCI-6024E and have our inputs set up in differential mode. We can get one channel to read but when two are connected we have problems with our readings being affected by each other. I have attached the vi file so if anyone can be of any assistance it would be much appreciated. We are beginners here so please be as specific as possible and dumb it down if necessary.
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ICtester.zip ‏214 KB

Hi Rylon-
It sounds like you are seeing ghosting of signals between your channels. KnowledgeBase "How Do I Eliminate Ghosting From My Measurements?" should be helpful in reducing this effect.
KnowledgeBase "Seeing the Same Signal on Several Scanned Channels, Especially when No Signal Is Conn... may also be pertinent if you are leaving the channels you're not testing without connections between testing channels.
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DAQ 6008 need to be reconnected

Hello,
I have a problem while performing a voltage measurement using DAQ 6008 board;
I need to reconnect the board each time I want to measure otherwise if I run the program, stop it and after that run it again
I receive the error 200284 saying that some or all of the samples requested have not yet been acquired.
Any suggestion is welcomed.
Thanks, Chipet
Solved!
Go to Solution.

Hey Chipet,
I looked into this error code for a little bit and found this article that goes over the some common reasons for getting it:
http://digital.ni.com/public.nsf/allkb/FEF778AD990D5BD886256DD700770103
I'm not sure where this is occuring in your VI, but I'd imagine it happens when you reads the samples. Adjusting the type of read you're doing (finite vs continous and the corresponding settings) could be helpful. Here is another article that goes through some of the more common DAQmx functions and when to use them:
http://www.ni.com/white-paper/2835/en
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Hello all!
I have a doubt concerning the Differential Mode in DAQ M series board. In the board's manual is saiing that the voltage limit is -10 to 10V, but somebody knows if this limit is always referenced to ground, or in differential mode is comparing with the +8 channel (ex. for channel 0 - voltage diference between ch0 and ch8).
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Paulo,
differential mode means that you measure the difference between two input channels. The channels used for this on E- and M-series boards is n and n+8. The difference between the channels might go up to +- 10V. So there is no ground reference in this type of measurement.
However, the device has a limited capacity against overvoltage. So if the offset of either of the channels succees a certain value in regard to the ground of the measurement system (the gnd of your PC), you could possibly damage your hardware.
Therefore it is recommend to use "BIAS-resistors" in such cases (or if you simply don't know the offset).
You can find a very good image on possible ) recommended connections in your DAQ-help. Open the DAQmx Help and navigate to DAQmx Help >> Measurement Fundamentals >> Signals >> Analog >> Connecting Analog Input Signals >> Measurement System Types. Just activate that entry (should have a "book" icon) and in the right side, you should see a something like a reference poster. I suggest you to print it out....
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[EDIT]: corrected a typo
Message Edited by Norbert B on 02-26-2009 08:03 AM
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I have copied my iTunes library onto a new computer, but when I play back the songs there seems to be random "miss" or "drop out". No probs with old computer, just the new one. I'm onto my third new computer - same problem. Any suggestions please?

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Medir Temperatura usando Termopar tipo J y la DAQ 6008

Muy buenos días. Les pido disculpas ya que este tema se ha tocado en el foro y les agradecería si atienden mi consulta.
Quiero adquirir con LabVIEW una señal de temperatura usando un termopar tipo J. Estoy al tanto que es necesario amplificar la señal. Pero donde necesito ayuda es respecto a la tercera medida de referencia (temperatura ambiente). No sé cómo exactamente tengo que corregir la medida que me darán las puntas de la termocupla.
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Muchas gracias.

Duplicated post
http://forums.ni.com/ni/board/message?board.id=6170&message.id=7949#M7949
Abel Souza
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Ayuda con proyecto fuzzy y tarjeta DAQ 6008

Hola buenas noches,
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Temp.zip ‏549 KB

Que tal.
Despues de revisar los dos codigos encontre los siguiente: en el codigo simulado se presenta la siguiente situacion
Sin embargo cuando trabajas con la DAQ haces lo siguiente.
pienso que eso puede ser el error. Edite tu codigo pero debes verificarlo para ver si es lo que necesitas o sigue presentando errores.
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CHALLENGER
K U D O S __ B I E N V E N I D O S
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Control Fuzzy Temperatura PG test tarjeta 6008.vi ‏329 KB

9205 differential voltage wiring

I am using a NI 9205 to measure differential Voltage.
I am a bit confused on the wiring. It appears that the wiring diagram shows that all low side signals ( -) should be tied to common which is tied to ground.
It seems if I do this, then I am not truly measuring a differential voltage, but RSE voltage.
I have read the manual and the NI field wiring tutorials, so please don't point me there, or post a picture, I am fully aware of what they look like, and still don't understand
them as well as I want.
Thanks for any help.

Where COM should be tied depends on the voltages that you plan on measuring.
There are several relevant voltage limits for the NI 9205 to consider:
Measurement Range:±10V max
The module can only measure a signal that is a maximum of 10V between the negative terminal and the positive terminal. The negative terminal in this case is either AI - for differential measurements, AI Sense for NRSE measurements or COM for RSE measurements. This is the range that the device can actually measure signals
Maximum Channel to Channel Voltage±30V max between any channel and COM
No channel (AI, DI, or PFI) should be more than 30V from the COM terminal. Any more than this and the module may be damaged.
Maximum Channel-to-earth Voltage±60VDC (±250Vrms for the Spring Terminal version)
This is the maximum potential that can be sustained between the COM terminal (or any other terminal) and chassis ground before the isolation barrier is damaged. The isolation barrier can withstand higher for short periods of time, but nothing over this value should be sustained.
So, the answer to your question depends on the voltages you are measuring. If all of the signals that you are measuring will be withing ±10V of earth ground, the easiest solution is just to tie COM to the chassis ground lug. If the voltages need to be between 10V and 30V from earth ground, you are certain they won't float out of this range, and you are measuring differentially then you can again tie COM to chassis ground as well. If the voltages must exceed 30V from ground, you'll need to tie COM to something that ensures that all of the three above conditions are met.
For example, if you are measuring signals that vary from 40V to 60V, you'd tie COM to a 30V power supply to ensure that it stays withing 60V of earth ground and within 30V of the highest signal (if you are measuring differentially or NRSE). If you were measuring in RSE mode, you'd tie COM to a 50V power supply to keep it within 10V of each AI measurement.
Does this make sense? For most people, the signals will remain within 10V of earth ground and so just time COM to earth ground.
Seth B.
Staff Test Engineer | National Instruments
Certified LabVIEW Developer
Certified TestStand Developer
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NI daq 6008 simultaneously analog input

Hello;
For the NI 6008 card sampling frequency equal to 10 kS / s and it has 8 analog inputs, but if I will use the 8 analog inputs simultaneously, what is the value of the new sample rate for each input analog obtained during an acquisition in labview?
best regards.

Duplicate post - http://forums.ni.com/t5/Multifunction-DAQ/NI-Daq-6008-and-Labview/m-p/3095362

NI 9264 Voltage Drop

Hi all,
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Thanks for your time and advices.
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Hi Henrik,
Thank you for taking the time to respond. I've attached the datasheet to my previous reply and I'm attaching the manual in this reply, for other people's reference. We are using FMA-2600 the standard version (no optional selection selected). On wiring, based from our understanding of the explanation, we just need to connect the positive pin of the 9264 to pin 4 of the connector and the COM on 9264 to pin 8 (Ground). Voltage input is being connected to another C-Series module and using the same method (Pin 6 Output signal to positive on the module and Pin 8 ground to COM). Can you please help to clarify what do you mean when you say "250Ohm resistor to ground..."?
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Attachments:
FMA-2600 Manual.pdf ‏3913 KB

How to connect pulse oximeter to DAQ 6008

What is needed to connected a Nellcor Pulse Oximeter for a adult finger to a DAQ 6008?

In order to connect any type of sensor, you need to know what sort of signal that the sensor is putting out. The 6008 has some basic analog inputs and static digital. I've only worked with the actual instruments. The various sensors often have a proprietary interface to the instrument and i'm not sure how much information is available on the sensors themselves. Perhaps you can check the biomedical forum to see if anyone has reversed engineered some sensors. If you can get some actual specs of sensors, it will be simple to say whether you can use a DAQ device to read them.

Voltage drop problem gd 65 z77

Hello,
I think i have a problem.
Mainboard Msi Z77a GD65, CPU i5 3570K.
Overclocked CPU to 4.5Ghz with a voltage of 1.265v from bios, but in windows it shows me as 1.248v , and whenever i use a stress program for cpu it shows as 1.224v-1.230v . (but at default bios settings 1.235v i never see any vdrops , was stable, and reason i increased the voltage was to avoid the Max Payne 3 black screen)
There is an option at bios called Vdroop offset control , i heard its for cpu idle state. But when i set this to %12,5 , instead it will drop at idle, it drops at load. I think LLC Load Line Calibration option is not on MSI bioses , if exist so i can setup with it. How can i fix this problem pls?
And btw when i use OC genie II button and start the pc, instead pc starting it keeps closing itself repeatedly.
My system :
İ5 3570K
z77a-gd65
Corsair VENGEANCE 8 gb 1866 mhz cl9 (4x2)
Zotac gtx 690
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Silverstone strider 1000w 80+silver
Bios version 10.5
not : when voltage is 1.235, it drops tp 1.200v at load and drops to 1.216 at idle.

Quote
the core voltage is auto and vdroop %75 Windows startup screen, blue screen.
Voltage 1250 vdroop 100%
Windows went through the processor core voltage when the load drops again
Vdroop is on automatic when voltage drop at least
So you say Vdroop set to 75% on the gd65 was lower than auto vdroop w/ cpuv set to auto? Did you verify this with a multi meter?
That is against the testing that both Bern and I did, might want to set to optimized defaults and update the bios to the newest beta.
<<<z77a-gd65 Beta Bios>>>
Make sure to use the forum flash tool: >>Use the MSI HQ Forum USB flasher<<
Here is an example of how vdroop effected the "auto" Cpuv on my z77a-gd80. I'll try to find Bernhard's that was performed on the gd65 as well.
The test I linked to was using a turbo overclock much like this:
https://forum-en.msi.com/index.php?topic=159647.0
Here are Bernhard's results on the same mobo, but both of these were done with a SB CPU.
(Linked with his permission)
If after the bios update your vdroop behaves differently, I would love your feed back or even a similar test showing the different behavior.

MOVED: voltage drop problem gd 65 z77

This topic has been moved to Overclocking, Undervolting.
https://forum-en.msi.com/index.php?topic=162022.0

Quote
the core voltage is auto and vdroop %75 Windows startup screen, blue screen.
Voltage 1250 vdroop 100%
Windows went through the processor core voltage when the load drops again
Vdroop is on automatic when voltage drop at least
So you say Vdroop set to 75% on the gd65 was lower than auto vdroop w/ cpuv set to auto? Did you verify this with a multi meter?
That is against the testing that both Bern and I did, might want to set to optimized defaults and update the bios to the newest beta.
<<<z77a-gd65 Beta Bios>>>
Make sure to use the forum flash tool: >>Use the MSI HQ Forum USB flasher<<
Here is an example of how vdroop effected the "auto" Cpuv on my z77a-gd80. I'll try to find Bernhard's that was performed on the gd65 as well.
The test I linked to was using a turbo overclock much like this:
https://forum-en.msi.com/index.php?topic=159647.0
Here are Bernhard's results on the same mobo, but both of these were done with a SB CPU.
(Linked with his permission)
If after the bios update your vdroop behaves differently, I would love your feed back or even a similar test showing the different behavior.

How to read multiple voltages from DAQ at same time?

Hello all,
I am attempting to read multiple voltage inputs to my USB-6008 DAQ but when I try to read a second voltage, I get an error saying "Erorr 50103 the resource is reserved." Someone in another thread said:
"The reserved resource is your DAQ board. You should not be using two separate simultaneous tasks for the same DAQ board. You should use a single task with two channels configured."
So I made multiple channels in one task, but I don't want to read all the channels at once. Is there a way to specify which channel of the task to read? Or is it not possible to acquire multiple voltages from the DAQ at all?
So the question boils down to: if you have 3 different voltage inputs into your DAQ, all corresponding to different components, is there a way to be tracking and reading all of them at the same time?
Thanks a lot

shahidi124 wrote:
Hello all,
I am attempting to read multiple voltage inputs to my USB-6008 DAQ but when I try to read a second voltage, I get an error saying "Erorr 50103 the resource is reserved." Someone in another thread said:
"The reserved resource is your DAQ board. You should not be using two separate simultaneous tasks for the same DAQ board. You should use a single task with two channels configured."
So I made multiple channels in one task, but I don't want to read all the channels at once. Is there a way to specify which channel of the task to read? Or is it not possible to acquire multiple voltages from the DAQ at all?
So the question boils down to: if you have 3 different voltage inputs into your DAQ, all corresponding to different components, is there a way to be tracking and reading all of them at the same time?
Thanks a lot
I don't understand your question. You made a task to read all the channels at once, but you do not want to read all the channels at once? And you want to track and read all the channels at the same time?
You need to explain it a little bit better and add some code of what you have done so far. A task will read all the channels in the task and give you the results so you can track them. So I am confused.

Random Differential Voltage Drop (DAQ 6008)

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