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Old August 16th, 2018, 12:59 PM   #1
Mad_Poet
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Profibus Termination

Dear Sirs,
I have three 'large' machines with lots of Profibus devices - Siemens PLC I/O boxes and Masterdrives and some MicroMaster drives. The computer has two PLC's inside it - one is a hardware PLC, and the other is a software PLC which uses a CP5613 card to communicate with its Profibus. (There are three Profibus's running off that one computer.)

I've built up a 'fake' fourth machine which is nothing more than the computers and PLC's of the system. It works . . . but my PLC's all show lots of errors - no doubt because I have no profibus's attached to them.

My question. Can I plug profibus connectors into the ports and enable the terminator resistor and (hopefully) correct at least some of the errors? Or will terminating, say, that CP5613 card damage something?

Regards, Poet.
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Old August 16th, 2018, 04:13 PM   #2
JesperMP
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Putting just connectors and enabling the terminators wont do neither good nor bad.


In order to figure out why there are errors on both hardware and software PLCs, you need to use STEP7 and check the hardware diagnostics.
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Old August 17th, 2018, 06:27 AM   #3
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Dear Jesper,
If it was a real problem I would. But I'm fairly certain that if I put this computer back into the real machine, it would work as expected.
http://www.plctalk.net/qanda/images/attach/jpg.gif

'Normal Run' has no red lights at all and the machine runs well.
The other one . . no Profibus hooked up. Seems like every time I boot one of these computers up on the bench with no profibus this is about what it looks like. Except that on the PLC_Motion BUSF2 is blinking red, and the PLC_Tracker has BUSF1 blinking red.

I think I will scrounge up three profibus connectors, with built in terminators, and see what happens.
Thanks, Poet.
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Old August 17th, 2018, 07:36 AM   #4
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Quote:
Originally Posted by Mad_Poet View Post
Seems like every time I boot one of these computers up on the bench with no profibus this is about what it looks like. Except that on the PLC_Motion BUSF2 is blinking red, and the PLC_Tracker has BUSF1 blinking red.
Almost certainly because the PLC as master cannot see the configured slaves.
To be certain, connect with STEP7 and check the hardware diagnostics. It will probably show that there are slaves that are unreachable.
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Old August 17th, 2018, 11:00 AM   #5
Mad_Poet
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Dear Jesper,
I believe you are exactly right. I'll try inserting a picture here in a minute.

Interesting thing, I'm fairly sure all of the PLC cards are WinAC Slot 416-2 's . . .
I open the Step 7, select the PLC, go to the PLC menu and select 'Hardware Diagnostics'.
That opens up with a lot of 'DPslaves' with a slash mark and the module information says they are not there. (On the live machine all I see there is the PLC - no DPslaves at all).

The PLC card, when selected and I click 'Module Information' I get an error box saying
"The inserted module and the configured module are not identical". OK, that goes away
and the information box comes up saying it runs OK. All three of the running machines do the same thing.
http://www.plctalk.net/qanda/images/attach/jpg.gif

Oh, adding the terminated profibus connectors did nothing at all.
Poet.
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