Dynamic Signal Acquisition

cancel
Showing results for 
Search instead for 
Did you mean: 

Can we sync 4472's and 4498's?

Can different types of DSA cards be synched together in one (or more) chassis?

For example can we add PXI-4498 cards to a system with several PXI-4472 cards?  

Can these synch automatically? or  be programatically synched?

I'm thinking about expansion of our dynamic data acq system, and this question keeps coming up.

 

thanks

0 Kudos
Message 1 of 8
(8,447 Views)

Good Afternoon Dave,

 

I think these links will get you going in the right direction.

 

How Can I Synchronize NI PXI-4472 DSA Devices Across Multiple PXI Chassis?

     http://digital.ni.com/public.nsf/allkb/6BC7EAF3153334C286256D0A004FA9D9?OpenDocument

 

How Can I Synchronize Two or More DSA Instruments?

     http://digital.ni.com/public.nsf/allkb/862567530005F09C86256736004EF995?OpenDocument

 

Can I Synchronize Different Types of DSA Devices at Different Rates?

     http://digital.ni.com/public.nsf/allkb/83C82B37411D837286257221006D5288?OpenDocument

 

Can I Synchronize a DSA Device with Other NI Hardware?

     http://digital.ni.com/public.nsf/allkb/AE63551CD4C4B24886256BE4004F4242?OpenDocument

0 Kudos
Message 2 of 8
(8,440 Views)

dsasynch.JPG

 

from http://www.ni.com/pdf/manuals/371235g.pdf

 

-gaving

Message Edited by gaving on 10-06-2009 04:53 PM
0 Kudos
Message 3 of 8
(8,380 Views)

Thanks Guys, for that info.

I am actually in the process of synching  PXI-4472B's and PCI-4472's across 2 chassis, so I had a pretty good idea that I could also do that for other DSA cards.

I guess the flip side of this question (or maybe more detailed)  is whether I could  simply plug the PXI-4498's into a PXI chassis with PXI-4472's in it and create a DAQ task with both types in it such that they automatically synch.

It seems all the KBs and examples only talk about the 447x's and 446x's.  would there be any different issues to consider withthe 449x's?

 

thanks

 

0 Kudos
Message 4 of 8
(8,263 Views)

Dave Karon wrote:

Thanks Guys, for that info.

I am actually in the process of synching  PXI-4472B's and PCI-4472's across 2 chassis, so I had a pretty good idea that I could also do that for other DSA cards.

I guess the flip side of this question (or maybe more detailed)  is whether I could  simply plug the PXI-4498's into a PXI chassis with PXI-4472's in it and create a DAQ task with both types in it such that they automatically synch.

It seems all the KBs and examples only talk about the 447x's and 446x's.  would there be any different issues to consider withthe 449x's?

 

thanks

 


Hey Dave,

The table I included is so that you can tell which "families" of DSA devices have a supported way of synchronizing.  There are two ways to do it.

1)  Reference Clock

2)  Master Sample Clock Timebase

 

447x devices use #2 exclusively while the 449x devices only support #1.  This leads to the answer of "no" you can't synch those two types of devices.  However, you can synchronize 446x with 447x (since 446x supports #1 and #2) and you can synchronize 446x with 449x (see chart).

 

I am curious now about your application since you're synch'ing across multiple chassis.  You must need a lot of inputs Robot Happy

 

-gaving

0 Kudos
Message 5 of 8
(8,258 Views)

It may also be possible to sync the data after the fact.  This requires that both the bank of 4472s and the bank of 4498s have a reference signal.  With re-sampling in LabVIEW, the signals then can be aligned to the reference signal.  For example a counter pulse, or a 2khz tone would work for a reference signal. 

 

Preston

 

Preston Johnson
Solutions Manager, Industrial IoT: Condition Monitoring and Predictive Analytics
cbt
512 431 2371
preston.johnson@cbtechinc
0 Kudos
Message 6 of 8
(8,252 Views)

Hey gaving,

 

The 449x thing is really a future thing.  What can we do if need to.

the multi-chassis thing is being built up (really just the PXI-6651 to RTSI and the data acq LV app.) now.

I had a PC with 3 PCI-4472 cards (so 24 channels). 

I had to increase channel count to ~48.  (56 would have been better, but lack of funds prevails).

The PC has 1 more available PCI slot, but in order to use it for a full length card, I would have had to do a lot of cutting and rearranging in the PC. 

So, the next consideration is an external PCI chassis. But, since the RTSI bus is limited to 5 "nodes" and I would need to synch at least 6 DSA cards,

so the external PCI chassis is a no-go, without using a timing controller such as the 665x which comes in a PXI version but not a PCI.

So, I turned toward the PXI chassis, with the new 4472 cards in there and my existing PCI-4472s in the PC.

I am using the only open PCI slot for the MXI controller card, using the PXI-6651 as timig controller to feed the timing signals to the STAR bus and cabling over to the RTSI bus.  

So with the 8 slot PXI chassis, MXI controller in slot 1, 6651 timing controller in slot 2, 3 4472B's, I have 3 open slots for future DSA cards without swapping or adding chassis. 

I guess the other overriding factor in future expansion is that the 14 slot PXI chassis limit synching DSA (at least 447x) cards up to slot 12, so only 1 NI-4472 cards in each chassis. (of course that's not an issue yet)

 

Dave

0 Kudos
Message 7 of 8
(8,249 Views)

Hi Preston,

 

The ref signal and resampling is something that I'll keep under my belt for the moment.

We will be recording a 1KHz IRIG signal, but I'm not sure yet that I have a free channel to input the ref signal into both banks of DSAs.

(not adding 4498s at this time only multi-chassis 4472s).

 

thanks

Dave

0 Kudos
Message 8 of 8
(8,246 Views)