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Mass Flow Controller: Control and Power Connection


Hello All,


I am trying to integrate an MKS mass flow controller with labview using a USB-6009.  I have done this before in graduate school but I forgot.  I believe I was able to walk myself through the steps but I would like to confirm with you guys prior to setting it up.  I have included a docx file for documentation support.


I will be connecting 3 mass flow controllers, back pressure regulator, and two pressure transducers (which I think the USB-6009 won't fit all of this). On an off note, is there an expanded version of this DAQ that will connect with all units?


But for now I am trying to figure out how the connections work so please continue with me.


Figure 1 is the schematic of the USB-6009 and Figure 2 is the 15-pin assignment for the mass flow controller.  I will purchase the MKS cable and cut one end off and wire the cables accordingly.  


AI 0 (AI 0+) connects with Flow Signal Output (Pin 2)

AI 4 (AI 0-) connects with Signal Common (Pin 11 or 12)


AO 0 or AO 1 connects with Setpoint Input (Pin 😎


And for Power please refer to figures 2, 3 and 4.

Since I am connecting multiple units I got a 13 amp current as I am not sure what the requirements are for each unit.

I am not sure if the power supply will be 2-wire unearthed or one earthed so I will go through both of them.


Two-wire unearthed

Connect positive (Red wire) from power supply to PIN 7 and connect negative (black wire) to chassis ground (PIN 15)


One Earthed

Same red to pin 7 and white to chassis ground (PIN 15).


If I remember correctly this is how they are supposed to be connected but I don't want to mess anything up before I confirm this.  


Thank you so much in advanced and your help is really appreciated.







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Over the same line of this problem (if someone gets a look at this post) I have a similar problem:

I have a MKS MFC and I cannot make it work. I'm using the NI 9381 (that works OK and make another 2 MFC correctly)

Over the connections, the pinout:

1 MKS Test Point*

2 Flow Signal Output (+)  -> to AO0

3 Valve Close Input (TTL low)

4 Valve Open Input (TTL low)

5 Power Supply Common - To the Common 

6 -15 VDC Input -> to the  -15 V PS

7 +15 VDC Input -> to the  -15 V PS

8 Set Point Input* -> To AI0

9 No Connection

10 Optional Input*

11 Signal Common

12 Signal Common -> to GND

13-14 No Connection

15 Chassis Ground. * Controller only

When I run my vi (and another one that I have just to test and give it voltage in units increment), it just give me about 0.23 Volts and it does not change and neither stop when I stop the while loop where I have the code.

I'm pretty sure is something about the connections, because the other 2 MFC work just fine (they are another brand, Brooks, so different pinout), but I cannot figure what will make the MFC send a constant, unstoppable 0.23 V.

And two questions: the power supply common is mandatory in the connections? (I didn't have it before and the same was happening, the 0.23 V, but now that I have it nothing changed, so just protection but not inferring in the performance?)

Having two grounds for the input and output are necessary or just one can work for a MFC?

Thank you!

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I know this post is pretty old, but thought I'd post since no one else has. I don't see anything wrong with your wiring explanation, although I would point out that it is difficult to verify your assumptions without having more information about the actual mass flow controller. If possible in the future, always put the actual controller model and attach a datasheet if possible. The thing that I would be most interested in seeing is the voltage levels for the input and output of the MFC to make sure it is compatible with the 6009.


As for whether there is another DAQ that could fit all of your sensors, NI sells tons of different models of DAQ devices with way more channels than the USB-6009. I'm sure there is one that would fit your needs, although to give an actual recommendation we would need to know the actual  AI, AO, and DIO channel count requirements.



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