Need hardware recommendation for chronograph.

[cdanprice]

I'm an noob, so bear with me:

I work at a ballistics range and we're having issues with our commercial
chronographs, so we want to build our own. I know labview will do it, but I
need to know what hardware we need to interface with our control systems.
Essentially, we need a way to monitor two open circuits, then as the
projectile passes through the two frames, each frame's circuit will momentarily close.
We have the frames and open circuits figured out, we just need a program that
can monitor and record event times. The system should wait for those two
signals, record them, and output the time difference between the two. This time will
then be used to calculate velocity. It should be a fairly straight forward
program to write but we don't know what hardware we need to purchase to
interface with our control computers.

Thanks for the help...

[Boatdrinks00]

cdanprice,

I am not sure of the velocities your looking to measure but at 5000 feet per second you're looking at one foot every 200 microseconds. I am not sure of the hardware you are looking at but you may want to check out the compact RIO with the 9423 module. The 9423 claims to have 1 microsecond I/O delay. If you need more resolution you can also take a look at the 9401 module. It claims to have 100 nanossecond I/O delay. 

As an avid outdoors man who is also unhappy with his commercial chrony, may i ask what you are using for sensors? I was thinking about butchering my  ProChrony Digital and creating my own. 

I hope this helps, good luck!

[cdanprice]

I'll definitely look into those. We're having issues with our current chronographs because like most, they rely on a beam of light to be broken in order to detect the shot. We're firing in an enclosed building, and firing small projectiles with very large powder charges (we'll say in excess of 6000 ft/s). Thus we have a very bright flash that confuses the chronographs. Further complicating the issue is the fact that we document our shots with high speed video, and the flash bulb from our camera interferes as well. We've done about all we can to shroud the chronographs, but light still finds a way in (usually from the gas stream that's following the round). Our solution is called  a "make" screen. It's just two sheets of aluminum foil separated by a sheet of wax paper. Attach a lead to each piece of foil, and when the round perforates the screen, the circuit closes. We've used this successfully to trigger our camera, but the camera has a built in sensor that monitors the open circuit and waits for it to close, making the system idiot proof. We need hardware that will do the same in labview.

[lowb]

To repalce your chronograph you will need:

1) PC

2) PCI 6250 Data acquisition Card

3) BNC 2090A Connector Block and cable

Do you have LabVIEW  Full Development System Sofware?