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 stability with 40" manometer 
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Joined: Tue Nov 12, 2013 12:48 pm
Posts: 103
Hi to all!
I wrote here to ask for a problem I have on every 2 bench I built.
The stability of manometer,isn't ever perfect....
For example in my personal bench today I have a 0.04 inch of pression and about 9cfm with the motor OFF.
I try some setting and a move the dm from his place,to move PC and other,but,nothing.....
In wich mode can resolve this problem?
If I enable "show raw value" I read an little,alternate and specular voltage,in rapid change,in the ch1 and ch2 voltage....
Anyone can help me?

The strange is I use the bench more times in this month and never had this problem.
Thanks!

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Fri May 08, 2015 2:02 am
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The number you see at rest is not added to your final reading, if you notice as soon as airflow starts the numbers roll back to 000 and then start counting up. This can happen so quick you never even notice it.

Channel Offset is used to make the numbers read 000 at rest

Take the average Byte Count from show raw values and put that number in channel offset ie if it shows 30 then channel offset would be 30

The DM should be setting horizontal on it's four bottom pads with the USB cable also kept away from any power lines inside the bench as best as you can. If you have it mounted vertically you effect the base calibration and it needs to be "field calibrated" to that position.

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Bruce

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Fri May 08, 2015 6:44 am
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Hi Bruce...
Unfortunately the error viewed in the CFM cell is added to the real measure. This is not a big problem if was not that this value chaqnge ever,from 6 to 10-12 or 18 cfm.
This is very big problem.
What I do?
No one effect takes the change on the setting windows,every value I put in the offset cell,normal or negative.
I try to move the DM,shield the power supply and other.
Please answer me.

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Mon Jun 08, 2015 3:58 am
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and another thing....i try to chang the usb cable,but I try 3 cable and with my cable is impossible to make the connection....the cable that come with the DM is special ?

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Mon Jun 08, 2015 4:41 am
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Other information:
I remove the dm from the case,put it so far from the bench,same thing.
Is very strange.
I think the problem is the entire DM,the fact they continue to made some CFM whit the power supply turn off is very strange situation.
Please anyone help me.

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Mon Jun 08, 2015 5:05 am
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Can you email me a video or screen shot of the show raw values window with no airflow and the DM on?

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Bruce

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Mon Jun 08, 2015 7:32 am
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Joined: Fri Jan 08, 2010 10:36 pm
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Quote:
I think the problem is the entire DM, the fact they continue to made some CFM whit the power supply turn off is very strange situation.
Please anyone help me.


FYI, The DM should show data even when the power supply is off as that is just the raw data from the Digital interface being read by the computer. The power supply just runs the actual monometer card not the computer interface.

hope this makes sense.

Rick


Mon Jun 08, 2015 8:00 am
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Joined: Thu Feb 25, 2010 10:37 pm
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Some dirt may be causing read error?
In the past pressure sensor (Automotive) the read error to be with small particles obstruction.

:idea:

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Mon Jun 08, 2015 12:03 pm
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Joined: Tue Nov 12, 2013 12:48 pm
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Today new big error....fortunately during the rec of the video.
At one point,the pc doesnt find the DM....
I try to restart the sw but nothing....For my luck befor the complete fail can show the problem of DM.
video as soon.

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Tue Jun 09, 2015 11:05 am
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https://www.youtube.com/watch?v=1oH8nYS ... e=youtu.be

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Tue Jun 09, 2015 11:14 am
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