Error 89136 when synchronizing two Digital Inputs PCIe-6535B

[pawel]

Hi

I used the Dev1/RTSI7 in the past for Digital Output to synchronize sample clock on two PCIe-6535B boards.

Now I am trying o use them as digital input and I get error:

Error -89136 occurred at DAQmx Start Task.vi:7220001

Possible reason(s):

Specified route cannot be satisfied, because the hardware does not support it.

Property: SampClk.OutputTerm
Property: SampClk.Pulse.Polarity
Destination Device: Dev1
Destination Terminal: RTSI7

I tried many others RTSI lines with the same result. 

Is there another way to synchronize the Digital Input cards to make them use the same sample base? 

I enclosed the simple vi showing the issue.

thanks

[Kevin_Price]

I used MAX to create a simulated 6535B and then checked out the Device Routes tab for RTSI connections (see below).  Looks like DO tasks can only route the source device's sample clock out to RTSI7 while DI tasks cannot route out to RTSI at all.

Both DO and DI tasks can route in from RTSI7 as a sample clock.  Do you have any other way to put a sample clock out on RTSI7 for the sake of your 2 DI tasks?  If either of your devices aren't doing DO during the time you need the sync'ed DI, you could make a dummy DO task that outputs the same default digital state continuously and route the task's clock out to RTSI7 for use by the DI tasks.   Otherwise, you'd need to involve a 3rd RTSI-connected device.

Or, much less elegantly, you might have to resort to physical wiring of PFI5 lines across the 2 devices.  DI can route a sample clock both to and from PFI5.

-Kevin P

[pawel]

Hi Kevin 

Thank you for looking into it. 

So you are saying I need to provide external sample clock to RTSI7 for them to sync together? This will be a problem. Providing 5MHz clean clock externally will be problematic.

I am so surprised NI made boards which cannot easily sync together.

For the other PFI5 idea. I thought the PCIe boards don't have these lines. 

Thanks for your help. 

[Kevin_Price]

Very speculative here b/c I've never worked with a 6535B or similar board.  But a closer and more creative look at the Device Routes chart suggests the following *may* be possible without any external physical wiring.

1. Before starting the tasks, use "DAQmx Connect Terminals" to route from PFI5 to RTSI7 on your designated master device.

2. On your designated slave device, use "DAQmx Export Signal" to route from RTSI7 to your DI Sample Clock.  Start this task first, before any sample clock will be present at RTSI7.

3. On your designated master device, use "DAQmx Export Signal" to route from your DI Sample Clock to PFI5.  Start this task now and both will be sync'ed.

4. When acquisition is finished, use "DAQmx Disconnect Terminals" to remove the route from PFI5 to RTSI7 on your designated master device.

-Kevin P