Synchronize PXI 4461 with PXI 4472

[manisha.singh]

Hi,

I am trying to synchronize PXI 4461 with PXI 4472. My setup is as follows:

PXI Chassis - PXIe-1062Q

PXI 4461 is in slot 2 with name 'PXI1Slot2'

PXI 4472 is in slot 8 with name 'PXI1Slot8'

PXI Chassis is running a 32-bit Windows Vista OS with NIDAQ mx version 9.3.0

I am trying to modify the "DSA Shared Timebase And Trig-AI and AO" provided with the DAQmx ANSI C examples. I am using sample clock timebase synchronization as PXI 4472 does not support reference clock synchronization.

Please find attached the C code that I am using.

I get the following error when I run this code

DAQmx Error: Source terminal to be routed could not be found on the device.

Make sure the terminal name is valid for the specified device. Refer to Measurem
ent & Automation Explorer for valid terminal names.
Property: DAQmx_SampClk_Timebase_Src
Source Device: PXI1Slot2
Source Terminal: DividedSampleClockTimebase

Task Name: Slave input task

Status Code: -89120
End of program, press Enter key to quit

However, when I look at the Device Routes in MAX, I see that the SampleClockTimebase can be routed to the PXI _Star. And I am under the impression that NIDAQmx will automatically use the PXI_Star and route as needed. I was also looking for a manual way in which I can export my master device ( PXI 4461's) sample clock timebase using the DAQmxExportSignal function, but could not find any.

Also am I correct in assumimg that channel expansion synchronization can not work with Hetrogenous devices ( PXI 446x with PXI 447x )?

Thanks a lot for your help! Please let me know if you need any further clarification about my setup.

Regards,

Manisha

The MathWorks

[manisha.singh]

Hey,

The channel expansion method to synchronize analog input channels with two DSA devices as described in this knowledge base also gives exactly the same error.

Basically these 3 lines of NIDAQ C code

     DAQmxErrChk (DAQmxCreateTask("Input task",&oneTask));
    DAQmxErrChk (DAQmxCreateAIVoltageChan(oneTask,"PXI1Slot2/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,0));
    DAQmxErrChk (DAQmxCreateAIVoltageChan(oneTask,"PXI1Slot8/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,0));

give the following error

NI Error -89120:
Source terminal to be routed could not be found on the device.

Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer for valid
terminal names.
Property: DAQmx_SampClk_Timebase_Src
Source Device: PXI1Slot2
Source Terminal: DividedSampleClockTimebase

Task Name: _unnamedTask<195>

Status Code: -89120

Thanks!

Regards,

Manisha

[Brad_K]

Hi Manisha,

The reason that the NI-DAQmx and DSA documentation says to plug the PXI-446x into slot 2 is so that it can control the PXI star trigger lines for the other slots. At the time this documentation was written, slot 2 was always the system timing slot, but this is no longer the case. I'll file a CAR about updating the documentation.

On the PXI-1062Q, slot 4 is the system timing slot. A PXI-446x in slot 2 cannot control the PXI star trigger lines for the other slots. Slot 4 is not hybrid-compatible, so you cannot plug a PXI-446x into it. Also, the newer hybrid-compatible version of the PXI-446x does not connect to the PXI star trigger pins, so it cannot be used to synchronize with a PXI-447x. You can find more details about DSA/PXIe compatibility here: Using PXI-4461 PXI-4462 and PXI 4472 devices in PXI and PXIe chassis

Brad

[manisha.singh]

Hi Brad,

Thank you for your reply.

This is very dissapointing for us. We bought PXI 4472 especially to be synchronized with PXI 4461.

I am still confused about certain points. So to further clarify:

1. I am assuming there is no way to synchronize PXI 447x and PXI 446x on any PXIe chassis. Is that correct? Even the PXIe-1065 18-slot chassis, has no System Controller Slot which can accept PXI modules and there are no PXIe 447x or PXIe 446x modules available.

2. The KB that you mentioned:  Using PXI-4461 PXI-4462 and PXI 4472 devices in PXI and PXIe chassis talks about PXI Star Trigger method. Is that same as the sample clock timebase synchronization method ( described in NIDAQmx documentation) and is called Star Trigger only because the sample clock timebase can be exported only to the PXI_Star bus.

3. What are the difference between synchronizating DSAs with PCI form factor and PXI form factor. If we move to using PCI devices instead of PXI, then this method of synchronization would work using the RTSI cable? So a PCI device would allow its sample clock timebase to be exported to a RTSI line but the PXI version will only export its sample clock timebase to PXI_Star?

4. Is there any way I can simulate a PXI/PXIe chassis to test my programs before buying the real hardware.

I really appreciate your time in helping us on this issue.

Thanks,

Regards,

Manisha

The MathWorks

[Kyle_K]

Hi Manisha, 

I have some responses that I hope help to clarify. 

1. Correct, the 4472 must use the Star Trigger lines in the chassis which the PXI 4461 cannot access.

2. They are similar, however the sample clock is not what is being exported with a DSA card. For these the clock source is a Master Timebase which is similar but has much higher specifications.

3. In the PCI form factor, the RTSI cable has its own connection on the PCI 4461 and the PCI 4472 and can therefore communicate. On the PXI system this connection is replaced by the connection to the backplane.

4. You can simulate your hardware in Measurement & Automation Explorer, however the simulation does not wait for triggers to send simulated data and therefore will not demonstrate synchronization.

Kyle K.