I need to hardware trigger SCXI-1100 when SCXI-1163r executes a port write

[plastic]

I am testing the response time for a miniature solenoid valve mounted on a manifold. The valve responds in less than 50 ms. I need the response curve of the transition from pressure to vacuum measured in mm Hg during a 60 ms cycle I have all sensors mounted and am getting good data. My SCXI chassis is connected to an AT-MIO16E-10. I am using Labview 5.1 in Windows 95. I want to cycle the valve and record the response. All SCXI-1163R digital outs are being used. There are several SCXI-1100 channels free. The SCXI has a Trig0 on the SCXI bus, I have read the manuals and searched on line but can't figure how to programatically use it. Thanx in advance for any help jim d

[DiegoF]

Hi Jim,

First, The Trig0 line mentioned in the SCXI-1100 User Manual refers to a control signal in the SCXI bus. It's used in the SCXI chassis to control the scanning in the diferent SCXI modules.
The acquisition is triggered in the DAQ board. The DAQ board controls the acquisition. To trigger an acquisition with SCXI you use the same VIs you'd use to trigger a DAQ board without SCXI.
In your case, the AT-MIO-16E-10 supports digital trigger. This means that you can use a TTL pulse to start the acquisition. This digital signal connects to the PFI lines of the board. Refer to the AT E Series User manual and the LabVIEW examples and help files for more info on how to trigger an acquisition.
The problem when using SCXI is that the PFI lines are no accesible
. To gain access to this lines you can use the SCXI-1180 feedthrough module. The SCXI-1180 is just a 50 pin cable that connects to the SCXI cable adapter (on the back of the chassis)giving you access to the PFI lines.

Hope you find this information useful.

Diego Funes.
National Instruments.

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We're nighty percent there, thanx. How do program so that I synchronize the SCXI-1163R output (24Vdc, all channels are used) and the TTL trigger. Can I use the DIO of the DAQ card to switch the 5 Vdc signal, Or the AO of the DAQ card, but this would be in a different program command. Again I need to trigger the acquisition when I energize the valve

[DiegoF]

Hi,
You can use a digital line to generate a TTL edge right before closing the relay. This digital line would be used to trigger the analog input acquisition. Of course, you'll have to add a little code to set the state of the digital line before you activate the relay. You'll just need to use an extra VI, "Write to digital line.vi". You can find LabVIEW examples on how to use this vi.
You access the digital lines using the SCXI-1180 feedthrough panel. One thing to keep in mind is that the SCXI system uses some digital lines to control the chassis and the modules. The reserved lines are 0, 1, 2 and 4. This means that you cannot use these lines. Check out the LabVIEW example "Leftover Dig with SCXI(E).vi" This example shows the reserved digtal lines
used by the SCXI system.

Diego Funes
National Instruments