01-14-2009 07:54 AM
I apoligize if there is already a forum topic about this but I have a couple of questions regarding the PXI 6071E DAQ cards.
The task is for numerous stations to collect synchronous data, as it stands each station has its own DAQ card we are leaning toward using the 10 PFI pins in between the DAQ cards by making hardwire connections in between the stations. What we want is to be able to set the Master station, aka Master DAQ card, through some software based application as the Master station in the lab is subject to change based on the experiement that may be running.
So here are the inquiries
Is there a way to connect PFI pins in between multiple DAQ cards and have only one of the triggering PFI pins on these DAQ cards act as a master triggering signal for the other DAQ cards. Can this master-slave establishment be set through from a software perspective, where every time a station turns on the master DAQ card has to be set with respect to other stations in operation.
I know these questions may be a little confusing but if there is any confusion please feel free to tell me, I was trying to keep the post small, and well I failed.
01-15-2009 12:22 PM
Welcome to the NI Forums! From what I gather it sounds like you are trying to synchronize multiple 6071E DAQ devices. The way that you would do this would be to export the Sample clock from your Master device over either a PFI or RTSI line to your other devices. Some good reading on the topic:
Timing and Synchronization Features of NI-DAQmx
M Series Synchronization with LabVIEW and NI-DAQmx -- Since you actually have E series devices, the section that you will want to look at is An Alternative Method: Synchronization by Sharing a Sample Clock
I am not sure what you mean by the following quote:
where every time a station turns on the master DAQ card has to be set with respect to other stations in operation.
If you post more information about what you need to do I'm sure we can provide more detailed help. The above links should serve as a good starting point for synchronizing your boards. Thanks for posting!
01-16-2009 08:12 AM
I just noticed that my first link seems to be incorrect, here is the correct link:
Timing and Synchronization Featuers of NI-DAQmx
01-20-2009 05:07 PM
We will be using the PFI pins over the RTSI since our DAQ cards (4 6071E series DAQs) are located in different chassis.
From my previous quote, what I was trying to understand the possibility to have any one (at a given time) of the 4 DAQ cards to act as a Master and the other 3 as slaves. This would greatly help us in having more possible design schemes and even give room to have more slaves/clients to be attached to the Master terminal in the future.
I'd like to thank you for the links you had provided, but since we are limited to only E series PCI devices which can't use the available RTSI bus, I was wondering if you had any other possible discussions or tutorials or forums or material we could work on?
Looking forward to your reply at your earliest convenience.
01-21-2009 03:32 PM
01-21-2009 03:48 PM
Ideally, you would be able to do this using T Clock , however, I don't believe that your E series device supports this. Are you using a timing and synchronization card in slot two of your PXI chassis? You can use the 10MHz backplane clock through the PFI line to synchronize these cards. I would recommend taking a look at how this is done through LabVIEW by looking at an example called Multi-Device Synch-Analog Input-Cont Acquisition.vi found by going to the Help tab in LabVIEW»Find Examples»Browse»Hardware Input and Output»DAQmx»Synchronization»Multi-Device»Multi-Device Synch-Analog Input-Cont Acquisition.vi. If I'm not understanding this correctly, or if you still have questions, please let me know!