Unable to establish a licensed session

treefort

Member
Join Date
Apr 2012
Location
British Columbia
Posts
25
Hello,

I have a Compactlogix L32E in my SCADA network that loses communications every now and then, and has to be power cycled to retain comms.

When I try to remotely go online with it, it says:

Failed to go online with the controller.
Unable to establish a licensed session with the device.

Error 701-80042546

Rockwell tech support insisted that I reflash the already up to date firmware, but that didn't work.

Anyone seen this before??

Any help is much appreciated!

Thanks.
 
I'm still getting this error! Rockwell insisted that we flash the firmware which did not end up fixing the problem.

Help please!!

Try deleting all the RSLinx Harmony Files, and the Reboot the PC.

Follow Mickey's Instructions here.

http://www.plctalk.net/qanda/showpost.php?p=298434&postcount=2

You may also have to cycle the power on the PLC if practical.

The other possible cause is a lack of resources on the CompactLogix. Is the PLC Memory close to full, or is it being hammered by multiple HMIs and PCs?

Stu....
 
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I have seen this before on a 1756 processor with Wonderware Intouch CE. It turned out that the wonderware had used up all of the "connections" to the PLC(glad it's different now.) I found this out with the Logix5000 task monitor tool.
 
Awesome, thanks guys. I will download the task monitor tool.

The PLC talks to a local HMI(panelview I think), and it talks to SCADA(Telvent) over a 1.2Mbps radio link.

The HMI continues talking to the PLC, but SCADA loses comms and my laptop cannot connect either. Looking at the diagnostics via http the max CIP connections observered was 4.

All that seems to fix it so far is to cycle power on the PLC.

Thanks again, I will try out the Talk Monitor Tool.
 
Comparing the troublesome processor with another there are a lot of connection requests, established, and closed for only being up for a couple days. I get 100% pings to the processor which is kind of weird because when I go online with my laptop from the other end of the radio link I get kicked offline every 5 minutes or so. I've also tried playing with the timeout settings in RSLinx without luck.

I can try installing a temporary PLC in place of the troublesome one to eliminate the PLC, but I am leaning towards the radio repeater being the problem. We had to set the retries in the radios to 8 in order to obtain 100% pings, and this is the only site talking through the repeater.

Any thoughts??
 
Thanks for the reply Mickey. I tried changing the CIP messaging parameters but after 5 or so minutes RSLogix came up saying it can't communicate with RSLinx again.
 
There's an RA Knowledgebase document, ID# 74127, that describes that error code in a little more detail.

How much free memory do you have in the controller ? Is the PanelView application particularly intensive with trending or a very large number of tags on scan ?

My guess is that you're losing a lot of packets, and therefore timing out a lot of CIP connections.

PING is a good little tool for verifying basic connectivity and latency, but getting all your PINGs through doesn't tell you much about overall performance. PING is a tiny packet... ordinary TCP traffic is a bunch of large ones.

You don't have to be a network guru to get useful information from Wireshark; if you run it on your RSLogix 5000 PC then run the Analyze -> Expert Info feature to get an idea of how many retries and repeats you're seeing on the link.
 
Truly sorry for the late reply. I tried twice and both times my session timed out before I clicked reply, and there is no pressing back with this site to copy your message.

Anyhow, thanks for the reply Ken. You were right with packet loss. The repeater had a ton of interference. I tried filtering zones but could not get it perfect.

I have since then switched radio networks to a licensed frequency system. Bad thing is the radio network is alot busier and is only 19.2kbps vs. the 1.2Mbps radios before. And turns out Rockwell's ethernet protocol is highly unefficient. Everything is talking, no more licensed session errors so far, but the comm stats for the RTUs on the new radio network have went from 100% to around 80%, and a lot slower.

I have SCADA set to poll the poll the 2 PLCs(RSLinx) every 5 minutes and the RSLinx OPC topics poll intervals set to 10 minutes so RSLinx doesn't talk over SCADA talking to the RTUs. If I upgrade the radios firmware I can enable a TCP proxy mode where it filters the uncontrollable AB PLC keepalives from going over the air. Im hopefully going to try that tomorrow but am a little concerned that the keepalives aren't the only issue. The other option I'm thinking is to use a virtual serial port and talk df1 to the PLCs which should be a lot more efficient, but getting the approval to install third party software is like pulling teeth.

If anyone has any suggestions on getting SCADA to talk to these 2 PLCs using the ethernet driver more efficiently please let me know. Do I only need to woryy about the TCP keepalives or is CIP going to be an issue too?

Thanks!!




I
 
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Same issue with L61 processor v19.11

I was unable to go online with one of our PLC's this morning seeing the same message "Failed to go online with the controller. Unable to establish a licensed session with the device."

I called tech support. They advised me to shut down communication between the PLC and it's HMIs. I did so but still no connection. Finally they recommended cycling power to the PLC processor. I did this and then was able to connect. Cause is still unknown. Support suspected not enough available free memory - but I check and had about 35% free.

The issue happened once and has not returned since.
 
I'm pretty sure my problem was poor communications. I replaced the unlicensed radios with licensed radios and haven't had the problem since. Thought I'd let you know.
 

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