share/simultaneously control 1 USB device from two computers

[nkhoa]

Hi there

I'm grateful for any insight regarding this matter.

Our laser system has a digital frequency synthesizer that has been under controlled by computer-A. Primarily, during run time, computer-A just "hooks" to the synthesizer and reads frequency values from it, and does not alter any properties of the synthesizer. 

Because the manufacture doesn't really share any LabView to change, forexample, the reference frequency, of the synthesizer, we need to write our own labview program for this. We can't use the same computer because the orignal software already binds into the USB-connected synthesizer. 

Therefore, we think we should get usb switch of some sort to share this synthesizer with a different computer_B. http://www.usbgear.com/USB-Sharing.html 

My concern is that whether this is possible. The USB device will be simultaneously read from computer_A and write from computer_B. 

Any advice or recommendation will be so great!!

[JÞB]

This will not work.  There is allways a 1:1 correlation between USB port and USB device.  The switches disconect all but one port. Even the automatic switch will cause all ports but the commanded one to disconnect.  Since USB is Plug-n-Play both OS's are going to go nuts over the repeated connection/disconnections and this will never support simultaioneous connection to both ports.   You will need to modify the source code on Computer_A to add the functionality that the current software lacks.

[nkhoa]

THanks for your explain!!

very useful! 

seems like I have to find alternative way to do this. The problem is the vendor quite doesn't like the idea to release the source code to us 😞

any suggestion will be great! 

[JÞB]

Well, What its the history and condition of the code... Third party application, Password protected Block diagrams, does it run in the RTE or the IDE.  how much of the code would you need to refactor?

[nkhoa]

All we receive from the vendor is a binary .exe windows file. We have no idea about the source .vi files. 

[JÞB · Accepted solution]

Well then its a simple matter!!!!

Just log the service support request to add the desired functionality   Hope they have a good support team.

(Ouch- That stinks.)

[Process_Systems]

If I had to accept the limitations you have for a project, I would be tempted to try to feed the USB connected software from your exiting computer into a secondary computer, rather than directly into the synthesizer. Then, write your software in the secondary computer to intercept the incomming data from the primary computer, and have a shot at integrating your own proprietary commands withing your own program, then send the whole mess to the synthesizer from the secondary computer.This leaves you with a single connection to the synthesizer, but no need to physically switch USB ports.

Of course, this method has a ton of caveats. You need to be able to decode/interpret the commands comming into your software from the original computer, buffer them, and then programatically (within Labview) select which to send to the synthesizer.

I would suspect that this would be a great way to get your blood pressure up, and keep warm over the cold winter!

Whatever you decide to do, GOOD LUCK!

[nkhoa]

lol

The company is going around the bush and not yet released source code nor replied to me about my request 😞

[nkhoa]

I actually thought about using another computer to control the synthesizer. 

But, what you suggested here is out of the box :)) I will definitely give it careful consideration and one shot. My blood pressure might shoot off the roof, because if I mess up , I might cause the laser cease to operate. 

just curious: have u ever done anything like this?