using COM1 to measure two MFC devices

[springby]

i attached the example on the original post. i used the first file. 

when i'm using it, i change the unitID to control two devices.

but for both instances, the numbers just don't show up when the two devices are connected to the COM1.

is there a way to put two instances into one vi so that i can control the flowrates simultaneously???

that will be actually really great if everything works fine.

[Wayne.C]

springby,

I took a look at the vi in question.  My first comment is that the vi's from Alicat are very crude and I'm not surprised that they don't work.  I'll tied up the rest of the day and probably won't be able to do much more until tomorrow.  Perhaps another forum regular can take a peek as well.

In the mean time it would be very helpful if you could post any info you have on communicating with the MFC's through the BB9.

[springby]

Here is the info of the Alicat's BB9

"The BB9 is designed to help users quickly and easily connect up to 9 Alicat flow and pressure devices to a single computer using standard DC-62 type connecting cables. The BB9 is built into a light, yet rugged, composite chassis ideal for mounting in almost any location. A single RS-232 cable allows a user to independently monitor and operate as many as 9 Alicat flow devices from a single computer. The BB9 will also power the Alicat devices it is controlling. In installations that require more than 9 Alicat flow devices, multiple BB9s can be used to control up to 26 Alicat devices. The BB9 saves time and money by allowing users to quickly and easily connect multiple Alicat devices via a single point. The BB9 is also an ideal solution for multiple flow instrument installations where devices are a long distance from the control site. " the website is http://www.alicatscientific.com/products/accessories.php thank you for your help!!! i really appreciate it

[Wayne.C]

springby,

What is the exact model of MFC you are using?  There may be a better LV driver available from the NI website.

[springby]

it's MC-10SCCM-D/5M, RIN, GAS: N2

[Wayne.C]

springby,

I looked a bit more at the LV vi's you posted.  There is no way they could ever work.  Decided to check the NI Instrument Driver Network and found a driver that looks more complete and makes sense.  Code is still crude and lacks good error handling but I think it will be a better starting point.  You can find a driver ( NI lib ) for the MC series MFC here .  Try it out.  If it looks like it will work I'll explain what needs to be done to clean things up.

Just remember that because you will be reading both devices using the same COM port, you need to read one and then the other. 

[springby]

the new code definitely seems to work!!!!

i can see the values of two devices clearly on the "reading" file front panel.

so do i have to hook all things up so i can change the set point and then check the reading at once??

can you give me some tips on that? it looks like the new one doesn't have a complete program where i can input the setpoint and then check the changes.

thank you so much!!