Limiting Number of GE SRTP connections used by a Kepware HMI

dabomb4097

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Join Date
Feb 2012
Location
Chicago, IL
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Okay, so here's a fun problem I'm running into. I have an AB PanelView Plus 1500 talking to a GE PACSystems RX3i via KepServer w/ GE Ethernet.

The controller CPU, an IC695CPE305, has a built-in Ethernet interface that the documentation states is only for Programmer use, as it only provides two SRTP connections. Documentation says HMI's are not supported by this interface, but we want to run our HMI over this built in interface anyway and avoid having to add an additional $1800 ethernet module. The HMI is portable and used only for troubleshooting and an annual systems test, so its not connected all the time.

Doing some testing it seems to work anyway, despite being not officially supported. Sometimes the PanelView will connect to and see the controller, sometimes it won't. A lot of random rebooting of both the controller and HMI are needed to get communications up; but once it starts working it'll stay working. My assumption is that the HMI expects to be able to use more than two SRTP connections, and if the first two were not cleanly closed the controller holds them open and denies further connections, confusing the HMI.

Is there some way to tweak Kepserver's GE Ethernet driver to only use 1-2 SRTP connections so that it doesn't overload the limited "programmer" connections available on the built in Ethernet in the CPE305?
 
I don't know about tweaking the KepServer drivers but keep an eye on the firmware updates for the IC695CPE305 as GEIP has promised to open this up in a coming update.
 
Actually the way it works is that each Channel created in the server is going to create a separate connection so if you had 2 channels to connect tot he same device then there would be 2 connections. If you have only one channel then it is one connection.

It could be a keep alive setting on the Ethernet card. What kind of errors are reported in the server event log. They should be sent to the Rockwell event log as well.
 
There is nothing in the PanelView log except for warm/cold reboots, unless there's another log file somewhere I don' know about, or I have to do special setup to log other kinds of events.

I think the problem is in the PLC, when I look at the RX3i's fault table, when the HMI loses the ability to connect, the first fault in the table is:

Event Type 1b: SRTP Server Events
Event Type 1b indicates an SRTP Server exception event.

Entry 2: 9 “LAN system-software fault; resuming”
An attempt to accept an incoming TCP Connect request failed. Subsequent attempts to establish an SRTP Server connection will fail until the PLC is restarted.

That seems to describe the symptom we're seeing (HMI connections, and programmer connections, fail until PLC is power cycled). Its followed by several other backplane faults like "An attempt to abort a request sent to the Backplane Driver (BPD) failed." and "The Backplane Driver (BPD) was not able to process a request from SRTP Server or the corresponding response."

Of course, GE Support is no help since the documentation says using an HMI with this built-in Ethernet interface isn't supported, so they just tell me I'm trying to do something that's not supported and don't consider it a problem.

I know I'm trying to do something that's officially unsupported, but under certain circumstances it does work, and I'm just hoping to find enough work-arounds to get it running a little smoother than it is currently.
 
Last edited:
Yeah that does not sound good. We have an RX3i in house the we use for testing and I have never seen that issue. We routinely test with more than 1 connection to the device. You probably need to talk to someone with a more intimate knowledge of the controller then I have.
 
You can run the same setup on a desktop PC which will allow you to see the server event log. I think that what you will see in the log is a lot of device not responding messages. You may be able to reduce them by increasing the request timeout and the connection timeout for he device.
 
Looks like I was able to prevent the lockup by adjusting the timeouts in Kepware. I just doubled everything from the defaults and can no longer reproduce the failure as before.

Thanks all for the suggestions.
 

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