How can I communicate with a MKS mass flow controller via LabView?

[johnjl]

Hi,

I am  building a mass flow system, and I have purchased two flow controllers from MKS company with this model number: GM50A004501RMM020 MFC, AR, 50 SCCM, 15 PIN ANALOG (TIED GROUNDS), N.C. TEFLON, LCMA51CR1MM20. I also have a MKS 946 Vacuum System Controller with this model number: 946-US-FCNANA-NA CONTROLLER, 946.

I am new to LabView and instrument communications, so I don' t know where to start for the software part. I have downloaded the instrument LabView driver (the description says that it supports RS485 G Series Flow Controllers from MKS). Do I need to buy any adapters? Should I directly control the MFC or through the 946 controller? And where should I start with? Any tutorial link will be great.

I greatly appreciate your help.

[GerdW]

Hi John,

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@johnjl wrote:

I am new to LabView and instrument communications, so I don' t know where to start for the software part. I have downloaded the instrument LabView driver (the description says that it supports RS485 G Series Flow Controllers from MKS). Do I need to buy any adapters? Should I directly control the MFC or through the 946 controller? And where should I start with? Any tutorial link will be great.

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When you are "new to LabVIEW" and ask for "any tutorial link" you really should note the Training resources offered in the header of the LabVIEW board! (Courses are offered for free until end of April!)

• To start with the "software part" you should read the manuals for your MFC. It will describe how to communicate with the device and explain the communication scheme! It will also tell you, if your computer or that 946 controller is more appropriate for the control job…
• For RS485 you will (most probably) need an adapter as such ports usually are not provided with standard laptops/office computers. Any USB-to-RS485 should work, but using PCI(e) cards for computers is considered to work more reliable. (You may also think about using LAN-to-RS485 converters to allow better placement of converter next to MFC…)

[johnjl]

Hi GerdW,

Thanks for reply! According to the manual, the MFC LabView driver was designed for RS485, but my MFC is 15 PIN ANALOG. Does that mean I need a 15pinD-sub-to-RS485 adapter in addition to the USB-to-RS485 to make it work?

Best,

Lai 

[GerdW]

Hi John,

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@johnjl wrote:

According to the manual, the MFC LabView driver was designed for RS485, but my MFC is 15 PIN ANALOG.

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So the MFC was designed for RS485, but it doesn't provide any RS485 communication? Really?

What is the pin assignment for this "15 pin analog" connector? (Again: providing a link to a manual would be nice.)

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@johnjl wrote:

Does that mean I need a 15pinD-sub-to-RS485 adapter in addition to the USB-to-RS485 to make it work?

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There is no generic "15pin DSub to RS485" adapter!

RS485 needs just 2 wires, and you need to connect just these. Maybe you need to use a soldering iron to solder two wires to a DSub15 connector and connect the other ends of those wires to your RS485 port…