ALE111 module send failure

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Thread Starter

Shahzad

We are using ALE111 ethernet communication module for communication between HIMA H51q and SLC 5. we are facing frequent problems of communication link down. Could somebody please guide us to address this problem
 
R

Red Winemaker

I have a similar problem. We are using ALE111 Ethernet card with controller ADV10D to communicate with WAGO controller via Modbus TCP. Sometimes, ALE111 card hangs. During the operation of the controller, I have to remove the card from the slot and reinsert to continue working. Slot contacts are not the cause. Does anyone know the method to reset the card without turning off the power and removing the card from the slot?

> We are using ALE111 ethernet communication module for communication between HIMA H51q and SLC 5.
> we are facing frequent problems of communication link down. Could somebody please guide us to address this problem?
 
Hi guys -

I have noticed that the ALE111 card will hang requiring a cold boot (removal and reinsertion) if it gets hammered with to much of the wrong traffic. In our case the wrong traffic is a network loop somewhere on the ALE111 network - and I suspect it is broadcast/multicast traffic (of which we don't have much) which does the damage. We manage this by avoiding network loops and using RSTP and a few other techniques in case of mis-adventure.

For you - I suggest isolating "other" traffic from your ALE111 card, I suspect your problem will go away. Assuming this is successful - if you want to re-join the ALE111 to the main network you will need to isolate the cause of the corrupt traffic / packets - I suggest wireshark packet sniffing, and work out what traffic is on the network when it hangs.
 
Hi,

I think that it must be any problem with the ALE111 cards. In my network work a lot of devices from several producers but only these cards sometimes hang up. I'm sure that I don't have any loops in my network.

Some years ago I had problems with HIS stations. After some days of work, these stations had problems with communication and they must have been restarted.

When I asked local service of Yokogawa in Germany, they always answered that I had everything wrong in my HIS (too many programs installed on HIS, too many Windows updates, wrong configuration of antyvirus program, etc). After some time it turned out that Vnet card- Vl701 were wrong, actually they had wrong software.

I suppose that it may be similar in case of ALE111.

Does anybody know how to make restart ALE111 without reinsert it from a nest?

Best regards.
 
Hi Bolek,

As always prevention is better than cure. I demonstrated the ALE111 crash to Yokogawa about 4 years ago and their advice was to avoid the scenario where we overload the cards. Like you - we can make the ALE111 lockup "on demand".

I recommend you download wireshark and check what traffic you have on your network.

The ALE111 are all modbus TCP - try to put them in a corner of the network where they only see their own traffic. I assume you have the ALE111 on a common network to allow you access to other TCP services on the slave devices.

Definitely use smart layer 2/3 switches to choke multicast and broadcast traffic (i.e.; to 2000 pps) - I know this works as I have recently had a network loop which crashed a couple of ALE111, though only affected the section of network segmented by our layer 3 switch.

Do not connect Allen Bradley remote racks to your general purpose network - they generate a phenomenal amount of multicast traffic, which even with well configured IGMP snooping will cripple anything with a less than perfect TCP stack.

I was considering firewalling or VLANing sections of our network based on critically though to date have not had to go this far.

And no - I don't know how to restart an ALE111 without removing it from the rack.

I seem to recall offline loading the FCS will restart the ALE111 - but I'm not keen to retest.

Regards,
PB
 
Hi Peterb,

I'm very glad to read your answer. I think your clues are very helpful.

All my ALE111 cards are used to communicate with Simatic controllers and are physically connected to VnetOpen network (to the same switches) , of course with using other adresses than DCS. My network is based on NetGear GS724T, unfortunately only 2-layer switches. I must check if they have possibility to choke multicast and broadcast traffic. How do you think the value of 2000 pps will be OK for VnetOpen? Won't it cause any problem with Yokogawa DCS network? Should I turn on storm control for all switches or only for this one where the ALE111 card is directly connected?

I'm going to try RSTP but I've noticed when I turn on RSTP and make a loop outside the tree covered by RSTP, the port in the GS724T switch which is connected to the looped part of network goes to "d-disable" state. Even if the loop is interrupted this port can only be enabled by restart switch or by web-config.

Yesterday I tried Wireshark (latest version) but, what is strange, it can't see any traffic focused on the ALE111 cards. Probably it can't recognize protocol although ModbusTCP is turned on in settings. I don't think I will able to notice something wrong because my ALE111 card hanged up after two months of normal work.

Best regards
 
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