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Why advantech USB data acquisition cards stop working when they are using near electric Arc furnace or when heavy loads are switches on/off

I am using USB4704 ( Advantech data acquisition card). there is a signal processing piece of program in labview which demonstrait the different parametes of electric signals scaned by the DAQ card. 

 

the program is working properly in the lab. but it hang up or stop working as it is being used near Electric Arc furnace or where heavy load are switched. 

 

it is needed to be mentioned that there is a common mode inductor, and differenctial filter on the input of signal conditioner.

 

my major concern is if it is a good idea to use advantech products with labview in an industrial environment.  

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Message 1 of 9
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I have no experience with Advantech devices, but USB DAQ of any kind can be a problem in an industrial environment. USB tightly couples the computer ground and power supply to the DAQ device. Unless the device includes robust isolation, that ground is connected to the external environment. Ground loops and induced currents which are negligible to industrial equipment can cause problems from minor shutdowns as you have experienced to complete destruction of DAQ devices and computer.

 

Isolated sensors or signal conditioners and DAQ equipment designed for the environment are better choices. IT does not take much damaged equipment and lost time to more than make up the difference in cost.

 

Lynn

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Message 2 of 9
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Sounds like an EMC problem .....Smiley Surprised

 

First tests to find out where the biggest ammount of EMC is entering...

With the box connected to the PC and disconnected sens wires: Does it still hangs up?

Since EVERY wire is an antenna: How about using filters (shokes) in your power supply lines (PC and USB)  and the USB cable?

 

Provide a low inductive (star) ground  between PC, USB-device and the end(s) of your sensing wires...

 

 

and I would say it is always questionable to use an 'ordinary' PC with a USB device in such harsch surroundings

 

 

EDIT: This post just stuck in my PC.... and of course Johnsold answered 😄

 

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'


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Message 3 of 9
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Henrik,

 

I was worried that your post was stuck, so I jumped right in. As always you make good points.

 

Lynn

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Message 4 of 9
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Dear Johnsold:

 

The isolation is done. An isolating transofrmer is used to isolate the input power waveform from the signal conditioner input signal. 

 

I am trying to check the ground paths and any probable ground loop.

 

thank u for u advice.

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Message 5 of 9
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Dear Henrik,

 

Could you please expain more about the low inductive star between computer and ... ? 

 

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Message 6 of 9
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Ok, let's start from scratch.....

 

We have a harsch industrial enviroment,

power supply lines with spikes, brown outs, .... you name it..

Some nice EM sources (I like the arc furnace  )    a lot of dI/dt and dU/dt ...  will couple in every wire.

 

Your system crash/hang ....  why?

Software: Due to ?? some strange/disturbed data or unexpected error messages arrive and your software/LabVIEW/the driver/the OS can't handle it.

Hardware: Unexpected reset of the USB device, or parts in the PC cause the stall .....

 

and you told us that power cycling a bigger load also will cause ths stall....

 

Unfortunately my crystal ball unforeseenable dropped from my desk 😉 so ...eyes closed, heavely breathing,  I see ....   I  seee ..

a USB device!! .....   puhh.

 

Use a short, good quality USB cable, add some filter to the cable like this:

USBfilter.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and for the grounding: please provide a picture/schematic of your setup, including ALL cables and devices ....

 

I had a look at the 4704 manual and didn't found a lot information about the internal ground schemata ....  ask advantech for it!  AGND to DGND to 5V- power plug to USB supply to USB shield  ???

 

 

 

 

 

 

 

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'


Message 7 of 9
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Dear Henrik

 

I really appreciate your help.

 

here is a schematic of my signal conditioner board DSC_3173.jpg

 

Ans the solution you mention of using ferrite core for the USB cable didn't wotk out either 😞 

 

 

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Message 8 of 9
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AGAIN:

 

and for the grounding: please provide a picture/schematic of your setup, including ALL cables and devices ....

 

as noted in my signature:
“ground” is a convenient fantasy!!!

 

But more important: If you disconnect all sensor wires (replace them with a resistor to ground) , will the system still crash?

 

Next test: Connect only the ground/shield wires..... Crash??

 

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'


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Message 9 of 9
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