DCE modbus scan once a day

[DCIM_Support]

So according to my DCE Modbus TCP device list, DCE only scans the Modbus devices once a day.

Any thoughts on this? How to troubleshoot?

Regards,

J

(CID:130097691)

[DCIM_Support]

Hi John Smith, thanks for posting. Let's hope you find your answer here. 

Kind regards Ditte

(CID:130099183)

[DCIM_Support]

Dear John Smith,

Please describe in detail your question: do you want to poll the TCP/IP Modbus devices only once a day, or does your DCE-server have problems with the polling interval of the TCP/IP Modbus devices?

With respect.

(CID:130680473)

[DCIM_Support]

My DCE only scans the devices once a day and I would like them to scan on the interval chosen (every 5 minutes).

When I look at the "Last Scan Time" it usually only shows once in the morning and that is it. Looking at the trend graphs, it shows the data point only once a day...

DCE is NOT scanning the device every 5 minutes as it should.

(CID:130680960)

[DCIM_Support · Accepted solution]

Dear John Smith,

An interesting problem... What is your version of DCE software?

Have you tried restarting the DCE server?

Can you do DCE capture logs according to topic ?

Can you then analyze the text file /var/log/messages and identify any errors or problems with your TCP/IP Modbus device (by its IP address and Slave ID)?

With respect and wait for your answer.

(CID:130681868)

[DCIM_Support]

Apparently there is a Known Modbus Scanner issue which was fixed in DCE 7.5. It doesn't go into detail but maybe with the device offline or a register issue, it froze up.

Improvements to Modbus polling Modbus polling is no longer affected by prolonged network disruptions.

(CID:131958890)

[DCIM_Support]

Dear John Smith,

I'll correct you: in fact, these fixes were made in DCE-7.4.3 😀. For example, see my answer in topic .

With respect.

(CID:131958908)

[DCIM_Support]

Thanks again! I am running 7.4.1 so, yes I need to upgrade. Thanks again for the quick reply as well!

(CID:131958914)

[DCIM_Support]

Ok, thanks for the good feedback 😀.

(CID:131958919)

[DCIM_Support]

It is loaded with Errors in /var/log/messages

The errors are:

Modbus_session_open: open session failed - Too many open files

nbModbusScannerCreateScan: Error creating Modbus session on

failscan:Marking scan of with SCAN_FAILED resultcode.

Error creating scan for :MODBUS-TCP, No protocol scanner found

nbVarLibAccessContextCreateInNS: cannot open /dev/nbVariablesFree

all the are the same so I am going to go delete that device and see what that does.

(CID:130681811)

[DCIM_Support]

Dear John Smith,

I would, after all, reboot the DCE-server first and watch for some time for the problem TCP/IP Modbus device.

With respect.

(CID:130681815)

[DCIM_Support]

That seems to have fixed my issue! The whole server is working better and the device scans have been re-scanning every few minutes now!

Thanks for the help! I will keep watching it and see.

I have another issue where the device discovery is slow and shows "initializing" for a long time but I will post that in another question.

Regards,

J

(CID:130681855)

[DCIM_Support]

Ok, thanks so much for the good feedback 😀.

(CID:130681866)

[DCIM_Support]

So it worked but there are other issues. Does someone here know what these errors mean?

nbModbusScan: Modbus_session_open: open session failed - Too many open files

nbModbusScan: nbVarLibAccessContextCreateInNS: cannot open /dev/nbVariablesFree

(CID:131336303)

[DCIM_Support]

Dear John Smith,

I will not prove, but the reason for the above problems can be, for example, problems with JVM, similar to those described in topic . What is your version of DCE software?

With respect.

(CID:131337115)

[DCIM_Support]

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