PCL stops when 1588 synchronisation is performed

[CyGa]

Hi,

I'm using VeriStand on several CompactRIOs placed on the same Ethernet network. Each CompactRIO is part of my System Definition and creates a versatile acquisition system.

In order to synchronise the samples timestamping on each targets, all controllers are running TimeSync over 1588 protocol.

In order to ease the configuration of the system, each cRIO avec the same 1588 priority (default 128). And we expect the master to be determined quickly when the targets turn on. When the targets are turned on the network topology do not vary (no device addition / removal).

We've observed that sometimes the 1588 master changes from one target to another, forcing the clocks to resynchronise on all targets. When that happens, we have an error from VeriStand saying that the PCL has stopped. And indeed our custom devices do not run anymore.

Have you observed such behavior ? Is there a turnaround / quick fix for this ?

[Jiri_K]

Be sure, that you have one defined master. It is defined by priority. If the targets has the same priority and there is some network issue the negotiation for master become again...

Some reading about synchronization. Only partially valid for cRIO. http://www.ni.com/white-paper/14637/en/

[CyGa]

Hi Jiri,

thank you for the link.

But as described in my previous post, I cannot ensure that a specific cRIO will be a master. It has to be determined automatically by the 1588 protocal scanning on the network which cRIO will best provide the synchro data (master).

In any case, lets say that I have one cRIO with 1588 priority set to 64 and another one with 1588 priority set to 128 (so no master flip flopping I would guess). Deploy your system. Open MAX and change the hour of the master =» the PCL fo at least 1 cRIO will be stopped (error message from veriStand).

Why is that ?