If your cards are PXI, than the two AWG’s can have synchronized clocks by using NI-TCLK. I have linked some great explanations about NI-TCLK below. If you are using LabVIEW, examples using NI-TCLK can be found here: Help >> Find Examples… >> Hardware Input and Output >> Modular Instruments >> NI-FGEN >> Synchronization.
I was unable to produce the same results as you describe – what example program were you running? I used the example ‘niFgen_Arb_Synchronize_Example_(TClk).vi’, and the screenshot below (TCLK Sync.jpg) is my result. I also used the example ‘niFgen_Arb_Synchronize_Sequence_Example_(TClk).vi’, and ‘sine wave Sync.jpg’ was my resulting waveform. Please note that you may have to look closely at the pictures to see both channels, but they are both there.
What device are you using as a scope? (benchtop? NI PXI-?? ) Are the signals generated properly individually? Are you generating the exact same signals? How long have you had these cards, and have they worked properly in the past?
Message Edited by David L. on 04-04-2007 10:48 AM
There are a few flaws with your code, which is why it is not operating correctly. The main one is that the while loop is placed around the entire sequence. This starts, initialize, etc…and stops the arbs every iteration.
I have attached an altered example VI (built in LabVIEW 8.2) which outputs sine wave at 10Mhz, with 2 different DC offsets. Please note that the DC offsets are only allowed to be set to ½ of what the gain is.
I did some testing using a PXI-1045 chassis with 8106 embedded controller, using a 5421(slot 17), 5422 (slot 11), and digitizing with a 5122(slot 15). I had the 5421 connected to ch0 of 5122, and 5422 connected to ch1 of 5122. With this setup, I could not reproduce the phase shift you are seeing.
I would like to ask that you detail your setup for me. What Chassis, cards (all in chassis), location of cards, connections, etc. What version of the driver do you have? (This can be found in Measurement and Automation explorer >> expand the software folder >> click on NI-FGEN, and the version will be on your right) Also, what version of LabVIEW are you using?
Lastly, please try the attached example. I want to see if you are getting the same problem when doing arbitrary waveform generation instead of standard function generation. Please post back with answers and pictures, as it is very helpful to see what you are scoping.
||18 Slot PXI Rack|
|1||PXI-PCI8331||Card + cable for PC to PXI rack. (PTC)|
|5||PXI-GPIB||GPIB Controller (PXI)|
|12||PXI-4071||7 1/2 Digit DMM|
|18||PXI-2532||8x64 crosspoint switch|
|4||PXI-5122||Digitizer, 14-bit, 100MHz, 2-ch., 32MB mem|
|2||PXI-5422||Signal Generator / ARB, 32MB mem|
|3||PXI-6552 *||20 Ch. High Speed Digital waveform/pattern generator100Mhz, 10mV resol., 1Mb mem.|
|6||PXI-2567||64 Channel relay driver|
|11||PXI-6723||32 channel DAC output card|
|10||PXI-6289||Multi-func 48ch I/O & 32ch DAC input card (18bit) & counters (2)|
|7||PXI-2593||High Speed 16:1 Mux (500Mhz BW)|
|8||PXI-2593||High Speed 16:1 Mux|
|9||PXI-2593||High Speed 16:1 Mux|
>Lastly, please try the attached example. I want to see if you are getting the same problem when doing arbitrary waveform generation instead of standard function generation. >Please post back with answers and pictures, as it is very helpful to see what you are scoping.I ran that VI and here is the plot, the waveforms seem in phase at 1MHz