LabVIEW Time Sensitive Networking (TSN)

Reply
This is an open group. Sign in and click the "Join Group" button to become a group member and start posting.
Highlighted
Solved! Go to solution

cRIOs to cRIO TSN

can two cRIOs use TSN time synchronization without a TSN switch?  (directly connected together to coordinate time).

i see the one example of directly connecting cRIO to cDAQ.  how about cRIO to cRIO for synchronized acquisition.

Stu
0 Kudos
Message 1 of 13
(2,207 Views)
12 REPLIES
Solution
Accepted by topic author srm@viewpointusa.com
09-06-2017 11:38 AM

Re: cRIOs to cRIO TSN

Yes.  They can also pass deterministic data between them.  This is the recommended path to get started for customers before adding the complication of setting up the network. 

 

On the cRIOs connect port 0 of one controller directly to port 0 of the other controller.  Then connect port 1 of each controller into your network with your PC so you can program and interact.  They will automatically synchronize (both RT and FPGA) and you can use the TSN VIs to send data between them. 

 

This example is set-up to run in that manner:

https://forums.ni.com/t5/LabVIEW-Time-Sensitive/Deterministic-Communication-TSN-API-Example/gpm-p/35...

 

Message 2 of 13
(2,205 Views)

Re: cRIOs to cRIO TSN

thank you.

it was not clear as the example shows the switch.  you also mention that deterministic communication is also possible cRIO to cRIO directly.  it is not clear to me how to do that as i thought that was a function of the switch to schedule the comm traffic.

Stu
0 Kudos
Message 3 of 13
(2,190 Views)

Re: cRIOs to cRIO TSN

Stu,

 

If you're using the switch, it will generate a schedule based on the network topology, we have to use this schedule in our API because it's when the switch is explicitly expecting a packet to arrive. 

 

If you're just using two end devices, there is no explicit schedule because there is a direct connection between the talker and the listener: there's no network infrastructure between the two devices that needs to handle the data. Simply choose a time for your talker to transmit the data, and choose a time later in the cycle for the listener to be ready to receive the data and the communication will work.

 

NOTE: You'll have to have a bit of time between your TX Offset and RX Offset even for directly connected devices so the packet can propagate through the NICs. If your delta between the offsets is too short, you'll notice that the packet will arrive at the RX Offset in the next cycle.

Ty Prather
Technical Marketing Specialist
National Instruments
0 Kudos
Message 4 of 13
(2,185 Views)

Re: cRIOs to cRIO TSN

Can multiple cRIO controllers be connected with Daisy chains?

Thanks

0 Kudos
Message 5 of 13
(696 Views)

Re: cRIOs to cRIO TSN

Today NI RT controllers (cRIO, IC)  do not have built in switches.  Each Ethernet port is a separate NIC to the processor.  These cannot be daisy chained, they must be connected through a separate switch. 

 

The cDAQ 9185 and 9189 and FieldDAQ IO devices all feature a built-in switch and can be daisy chained.  Please note these products support the time synchronization capabilities of TSN but do not support scheduling of traffic. 

0 Kudos
Message 6 of 13
(682 Views)

Re: cRIOs to cRIO TSN

What about the daisy chain  NI cRIO-904X?Both port 1 and port 2 can support Network Timing and Synchronizationaccording to the 904X specification 

0 Kudos
Message 7 of 13
(366 Views)

Re: cRIOs to cRIO TSN

Hi Raymond,

 

Hokie's comment applies to cRIO-904x targets as well. Right now, the cDAQ 9185/9 and FieldDAQ are our only targets with an integrated switch which enables them to daisy-chain. Both ports of the cRIO-904x do support networking timing & synchronization but since each port is it's own NIC, the ports will exist on different networks.

Austin
Product Support Engineer
National Instruments
0 Kudos
Message 8 of 13
(352 Views)

Re: cRIOs to cRIO TSN

Thanks.I get it.

I have another question, can one cRIO 904X and serval cDAQ-9185 make up a synchronous acquisition system(904X's port 2 connect to the port 1 of the master cDAQ-9185) without cisco TSN Router?

 

Thandks.

 

 

0 Kudos
Message 9 of 13
(340 Views)

Re: cRIOs to cRIO TSN

Hi Raymond,

 

The system topology you're describing would give you a synchronized network without needing an additional switch. This topology is described in the following document as a line topology.

 

Designing Distributed TSN Ethernet-Based Measurement Systems

 

 

Austin
Product Support Engineer
National Instruments
0 Kudos
Message 10 of 13
(333 Views)
Reply
This is an open group. Sign in and click the "Join Group" button to become a group member and start posting.