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PMAC seems to freeze - PcommServer problem


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I'm working on a plant with 3 Pmac2/PC104 racks, all connected to the same PC; 2 are connected with Ethernet and one with serial (since I need the DPRAM on ACC2P).

Each PMAC has its own HMI, communication server is PCommServer (Pewin32Pro2).


One of these PMACs (with Eth) showed a pretty strange behaviour: while working one of the axes executed the "end of cycle" movement in advance (but the others didn't) but, worst of all, the machine stopped responding to commands. I connected with my laptop to see what was going on and as soon as I established the communication the machine started responding again....

This thing happened twice, and while the anticipated end of cycle could have been triggered setting a variable to zero (but can't understand where) what is really puzzling is that the machine resumed from "freeze" state just by establishing a ethernet connection.


Another problem I have is that from time to time the PCommServer on the HMI crashes without apparent reasons.


The ethernet network at the moment is shared with other devices, and there is a server on the network that sends "Attacks" according to my Norton Internet Security

"OS Attack: MSRPC Server Service RPC CVE-2008-4250"


Will try isolating the machines from the external network, but I wonder what could cause such problems




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Hello all,

the freeze problem turned out to be related to the "unsolicited messages" (e.g. ERR00x that we sometimes see on the pewin32Pro wondow) that were not handled by the HMI and, after some time, filled the communication buffer causing the PMAC to freeze.

Connecting with Pewin32Pro2 causes a flush of the buffer, making the PMAC functional again.


So you need to either make sure that you don't get those messages or to flush the communication buffer from time to time.


Side note: a similar problem was happening on a grinding machine (based on a ADV400 system, connected via USB). Here, probably for noise /spikes , the USB commmunications fails from time to time and the machine "freezes". If I take off the USB cable and connect to the PMAC with another PC the machine starts over and finishes the job....

Also in this case leaving the Pewin32Pro open (minimized) seemed to be a patch for the problem.

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