Flow-BUS / FlowDDE

[Natig]

Hi, I am new to Labview.

I have 2 MFCs to control. I have used the Instruction Manual for the Flow-BUS Labview driver. Both MFCs are connected to COM4 through 1 cable. Now I know that by changing nodes I can go from one to another MFC. My aim is to have a simple code that can control both MFC by giving setpoints and, if possible, to have a plot of values. 

Now, there are 2 examples. The first one is very complex and there is no setpoint value function in the front panel. 

and the second one is very simple without stop button and etc. 

Which one should I use, and what should I add to these codes? 

Thanks in advance

[Natig]

I am using a template code provided by Bronkhorst flow-bus, but I get this error. What can be reason to this? and how can I solve it? It says timeout expired but there is no time function in the code. I have used Instruction Manual for Flow-BUS Labview driver. We have 2 MFCs that we want to control through Labview. 

[rolfk · Accepted solution]

Pretty much neither. They both assume only one controller on the bus!

But the principle is simple: You open the serial port once, then use the according VIs to set the setpoint or read back the current flow or setpoint, by specifying the according node number (node address in some Bronkhorst documentation) for each. Repeat and rinse the writing of setpoints and reading of values until you are done, then close the serial port.

[Natig]

Thank you for quick response.

I did the same in the picture that you uploaded. And got an error. 

[rolfk]

And what node addresses did you assign to your devices? Are you using those in your VI?

[JGoebel]

Hi Natig,

a timeout error is usually due to missing communication to the device (cable unplugged, missing non-ni driver ...).

Can you communicate with the device using MAX VISA Testpanel?

Here are further troubleshooting steps:
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019L3mSAE&l=en-US

Best,
Jan

[RTSLVU]

A VISA timeout error generally means your device is not physically connected properly or a communication setting (baud rate, GPIB address, etc) is not set properly or even the instrument itself is not in the proper mode for remote control.

[rolfk · Accepted solution]

Please keep related posts in the same thread. I already answered your other post. Flowbus is a multi device bus and each device has its own unique node address. If you try to address a device with a node address that doesn’t exist on the bus you will get a timeout error as nobody answers to your request.

So configure your Flowbus network according to the Bronkhorst documentation so that each of your devices has a unique address. You can do that by initializing the devices one by one with the little button on each device while connecting it to the power. You can also use the Bronkhorst FlowSuite software for that and also see each configured device and its assigned node address in that software. Note those node addresses and close the FlowSuite software and use those node addresses in your LabVIEW program.

[Natig]

It works now with the node numbers from the FLOW-BUS configuration.

Thank you, everyone, for taking the time to answer.