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Alicat Scientific MC series LabVIEW control

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In our lab, we have two Alicat Scientific MC series Mass flow controller. I was trying to control them directly through LabVIEW (read out the gas properties and set flow rate). There is a plug and play driver provided by AlicatScientific, I downloaded it and put the read and wirte VIs together.

I tested the plug and play driver separately before running the integrated VI which is made by myself. The VI for reading is working properly in our lab, but the writing VI doesn't. Could some one take a look at them and let me know what I should ask Alicat and what modification I should do on the VI.

I also attached the Write&Read VI which is made by me (I simply integrated Read and Write VIs) They both didn't work.

I am very new to LabVIEW programming, Need mentoring. Thanks

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Message 1 of 28
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Hi xiaoyiwonderfulman, 

 

I looked into the driver and noticed that it is all fairly simple VISA writes and VISA reads. As I do not have the instrument it is not possible for me to test it any further. 

 

I did also notice that it is not a National Instruments certified driver, and in this case I believe it would be most beneficial for you to contact the manufacturers support line for further assistance with this, as they were the people who wrote this driver. You can find their support at:

http://www.alicat.com/support/

 

 

-N

National Instruments
Staff Certification Engineer
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Message 2 of 28
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Hi there

 

The company where I work sells AlicatScientific devices, and often I do build instruments with them and also do software in Labview to control these instrumets.

 

What I learned from these drivers from Alicat is just I don't want to use them. They are too messy to work out. I just did build my own drivers. The protocol is too simple, and you can easily do "talk" with the Alicat FlowMeters by sending simple messages via Visa Write, and receiving the answers through visa Read, the manual explains very well how to do it.

 

You will need to do some work but its one more good oportunity to learn a little more. 

 

If you need some help, just ask. 

 

You can start with this simple visa write/read, please note that are many ways of reading the data, this is just one of them that I use.


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Message 3 of 28
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Xiao Yi,

 

I appreciate that you are new to programming in LabVIEW - I can recall how difficult it was in my early days.  That was a long time ago for me!

 

As others have suggested, the actual protocol for communicating with an Alicat is straightforward ASCII.  And the closest we have to "official" device drivers are the ones supplied by Alicat.  They are useable, but they are not a very good example of "clean" LabVIEW programming style.  This is of course just my opinion, but I know it is shared by others.  I will say that Alicat has improved their drivers, modestly, over the past few years.

 

The instruments themselves are excellent, and Alicat's tech support is superb and very responsive.  We have many, many devices at our location (easily over 100), and a full variety of functional types - mass/volumetric meters, flow controllers, and pressure controllers (both one- and two-valve styles), with flow ranges over six orders of magnitude (1 sccm up to 1000 liters/min).  The Alicat series 16 platform is very versatile.

 

For this reason I ended up writing my own driver library, with an effort to support all models with a common set of VIs, and including VIs to support all the additional functions the Alicat serial protocol exposes (range, identification, feature, status querying, controller loop tuning, etc.)  I also wanted to make a driver library which performs well, meaning it can get 20-50 readings per second from a device (depending on model, they vary in the amount of data they send).  Alicat's own drivers are lucky to get 2-3 updates each second.  (Not to be uncharitable, but the example posted by another person on this thread would suffer the same performance problem.  It unnecessarily loops, character by character, looking for a termination.  VISA does this for you, if you let it.)  I received (and continue to receive) technical details from Alicat to help guide me in understanding what all those registers do, and how the measured values are formatted, and how firmware revisions impact the device behavior.

 

From the code you posted, it looks like you took the driver from the Alicat website, then tried to use the NI instrument driver development wizard to start a driver design project.  You have a lot of extraneous stuff in there - the template VIs that the wizard offers up don't (again, my opinion) map very well to the task at hand.

 

I can't offer to completely guide you from start to finish in coding your first LabVIEW project, if that's what this represents.  But if you provide me with your email address, I'll send you a zip archive of my entire driver package, which is pretty fully documented.  It also includes a sample application (executable plus its source) which shows off what the driver VIs can do - a so-called "sandbox" project which talks to virtually any device type/range in the Alicat line, and allows you to inspect and change most of the device configuration.

 

Sorry for the length of this post - but if you really want to get familiar with LabVIEW, and get full use out of your Alicat devices, I would recommend you start here, get up and running, then take the time to trace through the code to see how it works.

 

Best regards,

 

Dave

David Boyd
Sr. Test Engineer
Philips Respironics
Certified LabVIEW Developer
Message 4 of 28
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Thank you for your help. However, since I am new to LabVIEW and Alicat Scientific does not offer any detail programming guide, would you show me what tutorials in NI website I should take a look at to get my first instrument control program done? At the time, I still have difficulty in understanding the templates supplied by Alicat.

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Message 5 of 28
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Dave offered to send you a well-written driver with an example application. That is a very good offer - even better than a link to tutorials. Searching the forums for "basics" turns up a few links:

http://www.ni.com/white-paper/5243/en

http://www.ni.com/white-paper/5241/en

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Message 6 of 28
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That's is a nice offer from Dave. I have been playing with Alicat's drivers and I have had problems with slow response and, more importantly, problems when I have multiple MFCs on the same RS232 line. You are suppose to be able to address them individually if you are using a BB9 box, but its not working for me. Smiley Sad   Those controllers have other quanities that would also be nice to pick off like pressure and temperature. I am glad some else worked it out.

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Message 7 of 28
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Thanks for your help Dave. Your sandbox really helped me out. I won't need to get any more drivers for my flow meters as they're all there.

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Message 8 of 28
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DavidBoyd a écrit :

Xiao Yi,

 

I appreciate that you are new to programming in LabVIEW - I can recall how difficult it was in my early days.  That was a long time ago for me!

 

 

I can't offer to completely guide you from start to finish in coding your first LabVIEW project, if that's what this represents.  But if you provide me with your email address, I'll send you a zip archive of my entire driver package, which is pretty fully documented.  It also includes a sample application (executable plus its source) which shows off what the driver VIs can do - a so-called "sandbox" project which talks to virtually any device type/range in the Alicat line, and allows you to inspect and change most of the device configuration.

 

Sorry for the length of this post - but if you really want to get familiar with LabVIEW, and get full use out of your Alicat devices, I would recommend you start here, get up and running, then take the time to trace through the code to see how it works.

 

Best regards,

 

Dave


Hi Dave,

 

i'm exactly figuring this kind of issue.

 

Would you please mind to send me this package also ?

best,

 

benoit

 

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Message 9 of 28
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Hi David,

 

I was wondering whether I coudl also receive your zip archive of your entire driver package. I have an Alicat Scientific mass flow controller which I would like to control through LabVIEW 2013. I would liek to loop and automate a gas experiment which normally requires manually adjusting the settings on the flow controller.

 

Thank you in advance!!!

 

Kind regards,

 

RideTheLightning

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Message 10 of 28
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