OPC Kewpare V5.8 OPC-UA Issues

Question

I've to do a migration from KEPServerEX 5.8 to KEPServerEX 7, step by step, using a BRIDGE KEPServerEX 7 solution, that initially it is connected in OPC-UA to all OLD channel/device/tags of KEPServerEX 5.8.

Then in a new Server with KEPServerEX 7 we migrate step by step each original channel, then connecting the BRIDGE to the new one migrated.

Finally we will have the BRIDGE only linked in UA Client to the new KEPServerEX 7 migrated, and no more to the old one KEPServerEX 5.8.

Now we are testing this migration scenario creating in Kepware 7 BRIDGE an OPC-UA Channel to Kepware 5.8 OLD, but we have some issue when the remote Channel in Kepware 5.8 is it self an OPC-UA driver.
In some cases, the tags seems to be unknown and in bad quality, why ?

The issue happen also if I try to read the remote TAGs via UAExpert tool

To understand/replicate the issue I have done also another example locally, in order to exclude network and OPC-UA configuration, both in Kepware 5.8 and in Kepware 7, explained below:

1) I created a Simulator channel/device/tag "TEST_SIM.TEST.T" with a RAMP T tag, just to simulate some values.
2) I created a first OPC-UA channel "TEST_SIM_UA_1.TEST.T" that connects to itself by retrieving TEST_SIM.TEST.T.
3) I created a second OPC-UA channel "TEST_SIM_UA_2.TEST.T" that connects to itself by retrieving TEST_SIM_UA_1.TEST.T.
4) I created a third OPC-UA channel "TEST_SIM_UA_3.TEST.T" that connects to itself by retrieving TEST_SIM_UA_2.TEST.T.
5) I created a fourth OPC-UA channel "TEST_SIM_UA_4.TEST.T" that connects to itself by retrieving TEST_SIM_UA_3.TEST.T.

Results:
A) Kepware 5.8 with the Kepware quick client, I see "unknown" already from the second OPC UA channel "TEST_SIM_UA_2.TEST.T", but in an unpredictable manner; sometimes it works, sometimes it doesn't, and the next OPC-UA Channel never work (all unknown).

B) Kepware 7 with the Kepware quick client always shows all the tags as good quality.

It therefore seems to be more of an intrinsic limitation of Kepware 5.8, regardless of the spaces, but rather the number of OPC-UA hops.

Exists some workaround to be used in order to create correctly an OPC-UA driver to all remote channel of Kepware 5.8 via OPC-UA?

NOTE: the OPC-UA configuration used is anonymous and without username and password

Many thanks.

Regards

Giuseppe

MKhatri · Accepted Answer

Greetings!!

Practical resolutions for the OPC UA tag‑quality issues encountered during the migration from
KEPServerEX 5.8 to KEPServerEX 7, without going into technical root‑cause details

Recommended Resolutions

Avoid multi‑hop OPC UA channels in KEPServerEX 5.8
Limit UA connections to one direct hop only, as deeper UA chains cause unreliable tag quality.

Connect KEPServerEX 7 BRIDGE directly to the base channels/devices in 5.8
Do not relay tags through other OPC UA channels inside KEP5.8 to prevent “Unknown” or unstable quality.

Use OPC‑DA instead of OPC‑UA for bridging 5.8 → 7
Kepware 5.8 has a fully stable OPC‑DA server and KEP7 includes an OPC‑DA Client driver.

Use static tag import instead of browsing when UA browsing is unreliable
Import tags manually into KEP7 to avoid quality issues during UA discovery.

Migrate channels step‑by‑step directly into KEPServerEX 7
Once migrated, point the BRIDGE to the new KEP7 channels and remove dependencies on 5.8 OPC‑UA layers.

Regards,
Mohit

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