05-13-2011 04:20 PM
I've poked around the KB a bit and didn't see anything related to my seemingly easy problem regard triggering with my PXI-6533. My device is named "Dev3" and the line I'm polling for a waveform is "Dev3/port0/line3". I want to trigger off of this same line to start my waveform but the only available options for the trigger source are PFI and PXI_Trig lines. I've attached a screen shot of my VI and of the source options for triggering. I'm using LabVIEW 8.6.
Andrew
05-15-2011 02:55 AM
Hi,
Have you looked at the manual/pinout for the device? I couldn't find a manual but it normally tells you which lines are PFI lines - it maybe the the line P0.3 is a PFI line. For example on the 6211, P0.0 is PFI0
Hope this helps
David
05-15-2011 10:32 PM
The 32 individually configurable lines of digital input and output on the NI 6533/6534 are grouped into four 8-bit ports, as shown in the following table. Dev1 in physical channel names is the default device name for NI 6533/6534 devices. You can change these names in Measurement & Automation Explorer (MAX).
Port | NI-DAQmx Physical Channel Name (Lines) | NI-DAQmx Physical Channel Name (Ports)1 |
---|---|---|
Port 0 | Dev1/port0/line0 — Dev1/port0/line7 | Dev1/port0 |
Port 1 | Dev1/port1/line0 — Dev1/port1/line7 | Dev1/port1 |
Port 2 | Dev1/port2/line0 — Dev1/port2/line7 | Dev1/port2 |
Port 3 | Dev1/port3/line0 — Dev1/port3/line7 | Dev1/port3 |
1This physical channel name refers to all eight lines in a port at once. |
For Ports 0 through 3, you can configure a port width of 8, 16, or 32 bits. To configure a 32-bit port, use the physical channel name Dev1/port0_32. To configure a 16-bit port, use channel names that refer to all the lines in multiple consecutive ports: Dev1/portP_N, where P is 0 or 2, and N is the total number of lines. For example, to combine Port 2 and 3 into a 16-bit port, you would specify Dev1/port2_16 as the physical channel.
The NI 6533/6534 has two timing controllers (Group 0 and Group 1) for high-speed data transfer. Each group contains four control lines which can time the input/output of data with hardware precision. You can use Groups 0 and 1 to perform the following actions:
If you are not using Group 0 and/or Group 1 as timing controllers for timed operations, you can use their control lines as extra data lines. These lines constitute Ports 4 and 5. The direction of these lines is not configurable—four lines are used as input only (Port 4), and four are used as output only (Port 5). On a per line basis, Port 5 lines can be configured for open collector generation.
Even though there are eight actual lines, the port widths are 4 bits. The following table shows the lines that make up Ports 4 and 5.
Direction | Line | Group | I/O Pins | Physical Channel Name (Lines) |
---|---|---|---|---|
Input | 0 | 0 | PFI 0 | Dev1/port4/line0 |
1 | 1 | PFI 1 | Dev1/port4/line1 | |
2 | 0 | PFI 2 | Dev1/port4/line2 | |
3 | 1 | PFI 3 | Dev1/port4/line3 | |
Output | 0 | 0 | PFI 4 | Dev1/port5/line0 |
1 | 1 | PFI 5 | Dev1/port5/line1 | |
2 | 0 | PFI 6 | Dev1/port5/line2 | |
3 | 1 | PFI 7 | Dev1/port5/line3 |
05-16-2011 01:01 PM
I put a jumper on my signal wire so it is now going into Dev3/port0/line3 as well as /Dev3/PFI0 for my trigger. DIO acquires signal fine until I insert the trigger VI. Now DAQmx Start Task is erroring out with
"Error -200904 occurred at DAQmx Start Task.vi:2
Possible reason(s):
Measurements: Start Trigger Type requested is not supported given the requested Timing Type.
To use the requested Timing Type, do not set the Start Trigger Type property. NI-DAQmx automatically selects a compatible Start Trigger Type setting.
To use the requested Start Trigger Type, select a different Timing Type.
Property: SampTimingType
Requested Value: On Demand
Property: Start.TrigType
Requested Value: Digital Edge
Task Name: _unnamedTask<31>"
05-16-2011 02:56 PM
Hello Andrew, this is Paul with Applications Engineering at National Instruments.
Just to be sure, you want to trigger a digital input off of itself, correct?
The best way to tackle this is going to basically be what you have already started on by using jumpers between the 2 lines. It may be possible to achieve this through internally rerouting the signal, and only using 1 hardware input, but this will likely create problems and be more complex.
We actually have a shipping example that demonstrates what you are trying to do. You are going to want to use a technique we call acquiring pre-trigger samples in order to ensure that your acquisition start coincides with the trigger, and that you don't miss samples in the delay. Essentially by pre-triggering we are setting up your device to read trigger samples ahead of time, sort of as a buffer, to ensure that we don't lose your actual data samples.
In this example will need to use both a DIO line as well as that PFI line with a jumper as you are already doing. To get to the example, in LabVIEW, please go to Help>Find Examples>Browse>Hardware Input and Output>DAQmx>Digital Measurements>'Read Dig Chan-Int Clk-Dig Ref.vi'
Let us know how that works out for you, and if we can be of more assistance.
Regards,
05-16-2011 03:02 PM - edited 05-16-2011 03:03 PM
the valid start trigger sources for the PXI 6533 are PFI6 and PFI7. Since your using PFI0 you get your error
05-16-2011 03:06 PM
What Jeff said is also true, I missed this when looking through your documentation, although I would still recommend using pre-trigger samples (with PFI 6/7) to ensure that you don't lose any of your original signal.
05-16-2011 03:09 PM
@Paul-D wrote:
What Jeff said is also true, I missed this when looking through your documentation, although I would still recommend using pre-trigger samples (with PFI 6/7) to ensure that you don't lose any of your original signal.
Someones gotta keep the blue bars honest!