Synchronize PXI FPGA 7841 with 4140 Source Meter with trigger

[moritzb]

Hi,

I work with a PXI system including a FPGA 7841  and a 4140 Source Meter Unit. The SMU is used to supply a sensor (DC voltage 3.3V) and I implemented an i2c protocol on the FPGA board to communicate with the sensor. Right now I need to trigger the output of the SMU with the FPGA card for a specific application. So I want to send a hardware based trigger signal with the FPGA 7841 and want to wait for e.g. a rising edge with the SMU before turning the supply voltage on.  I tried to implement this by setting the '/PXI1Slot2/PXI_Trig0' on the FPGA board as output and then set the output from low to high. This rising edge I wanted to detect with a DCPOWER VI before starting the output voltage. I couldn’t find a matching example and wanted to ask, if you have any suggestion how I could implement this in a stable way. For the SMU 4140 I use a single point source mode and dc voltage as output function.

Best regards,

Moritz

[=Jean]

Hi Moritz,

you can have a look to this white paper, explaining how to synchronize PXI modules with the inbuild RTSI with a really basic example:

http://digital.ni.com/public.nsf/allkb/67A6D7F36FB9C4C586257974007BA077

Also have a look to the datasheet of the 7841 for more informations about that. 

Hope that helps! 

[moritzb]

Thank you for your fast answer and the link. The tutorial seems just for FPGA cards. On FPGA I implemented it in the same way. Now I just have to figure out how I can read this trigger port 0 on the SMU card 4140. I don't have the possibility to read it like on FPGA. I just have different trigger options like the start, source and meassure trigger. I also don't have an opportunity to check if the trigger works correctly. Do I have to configure the trigger bus and route the backplane of the PXI system? If yes is there any documentation how to route the trigger bus of the backplane?

[=Jean]

Hi Moritz,

Once the signal is on the PXI backpane (means on the Trigger Bus), I think you easily can use it to synchronize the SMU.

You might find some example in the LabVIEW Find Example: Hardware Input and Output > Modular Instruments > Ni-DCPOWER.

You also can have a look to the help of the DCPOWER driver, which provide you a lot of information (look at digital edge, it is talking about the Trigger BUS..):

http://zone.ni.com/reference/en-XX/help/370736F-01/ni_dc_power_supplies_help/configuringtriggevents/

If you have the SSP, I suggest you to contact your local NI sales / support.

Hope it helps!