DP/DP coupler Profibus issue

Hi all,

We have a system with a CPU 315-2DP fitted with a DP/DP coupler. 158 0AD01-0XA0

Local profibus consists of CPU1, DP/DP (10 addr) and four drives (11,12,13,14 addr)

Second profibus consists of CPU2 (317-2 PN/DP )  master, lots of other nodes, plus DP/DP(4 addr)

After a power blackout, CPU1 dos not communicate anymore with master PLC

Checked with CP5512, network 1, all nodes are online ( 2,10,11,12,13,14)

After upload program CPU1 to PG, on hardwareconfig, online node 10 OK nodes 11,12,13,14 shows with red slash, HOWEVER they do communicate with CPU as drives values can be seen on HMI.

Checked with CP5512, network 2, all nodes are online ( 2,4 and all others)

After upload program CPU2 to PG, on hardwareconfig, online node node 4 shows red slah as it is not there, all other OK. So node 4 red slah, Status = Unknown, external error"

Comm is done by by SFC14/15 who returns -32607 = 80A1 and -32608=80A0 - "An access error was found when accessing the I/Os", which is logical if plc is not seeing the node.

Now there are two big questions.

1.How after a blackout a PLC is not seeing anymore a node who is present on network.

2. How another PLC, even if shows nodes with red slash still reading values from nodes?

Both profibus line are healthy. 1 is 1.5Mbps, about 50 meters fitted with DP terminator

Second line is longer 500Kbps fitted with DP terminator

Thank you for any hint

pim

Hello pimpîm;

Have you any active diagnostic LEDs on the DP/DP coupler after the electrical problem.

See the screenshot below, taken from the DP/DP coupler manual, chapter 6, Diagnostics.

https://support.industry.siemens.com/cs/ww/en/view/1179382

Please tell us what status are the LEDs, and what you can conclude from them.

Hope this helps,

Daniel Chartier

pimpim32

Now there are two big questions.

1.How after a blackout a PLC is not seeing anymore a node who is present on network.

2. How another PLC, even if shows nodes with red slash still reading values from nodes?

Both profibus line are healthy. 1 is 1.5Mbps, about 50 meters fitted with DP terminator

Second line is longer 500Kbps fitted with DP terminator

Thank you for any hint

pim

All misbehavings you had described above are painfully familiar to me, since I faced with this a couple of weeks ago. I spent about two days in order to force this boundle to function as I need.

I also wrote here, however, it seems there's very limited number of people here who know the ropes.

as concerning a valuable help: I would look at your project, the coupler wiring (24VDC) and dil-switches position are also interesting.

BR

Thanks for answers,

So, DP/DP LEDS : SF1,SF2,BF1,BF2,ON1 = OFF, ON2 = ON  ( solid green )

CPU1 LEDS : RUN,DC5V = ON ( solid green ) all others off.

I have drawings for CPU2, no drawings for CPU1.

Next move I will try reset CPU2 ( little difficult due to process constrains) also look after physical 24V original connections.

pim

Latest info.

Checking wiring, DP/DP is wired only on lower two connections ( 24 V DC from network 2 ) although 24VDC comes from local, network 1, measured 23.95VDC.

After shutting down CPU2 power we have CPU1  SF LED solid red, and DP/DP LED : SF1, SF2, BF2 LEDs solid red, ON2 = solid green.

After restoring power to CPU2 we have CPU1  SF LED solid red, BF LED blinking red , and DP/DP LED : SF1, SF2, BF2 LEDs solid red,  BF1 LED blinking red ON2 = green.

Shutting power CPU1 ( alltogether with DP/DP and terminator for network 1)

After restoring all LEDs become normal. CPU1 RUN and DC5V, DP/DP ON2

AND after communication restored. CPU2 is seeing DP/DP, going on HardwareConfig CPU2 node 4 does not have anymore red slah, diagnostic values on SF14/15 = 0  ....

So, same LED all green but now on good way.

Also discovered that, whoever installed the system, they put a "Reset DP/DP coupler" button on SCADA, wired to an output to go ON for 10 seconds. The output goes to a NC contact from a relay who supplies with 240VAC the power supply from CPU1  nice old fashion way reset........

Also I do think anymore network1 is so healthy. With system in auto, drives command from fieldbus, when trying to connect my CP5512 card, or when trying to click Monitor/Modify SF on CPU1 goes red, BF blinking for 2-3 seconds , after that recovering by itself. So when time will come I will try to lower the baudrate to 500Kbps.

Even if I am not sure what happened  here and why it recovered think I will stop here. Now it is working. ( be back when will happen again...)

Thanks all for info.

pim

I am noticing that DIL switch PS is on for network 1, but actual 24VDC is connected on network 2.

Does that have any bad influence?

pim

Hello pim;

From the manual already suggested...

Tell us if setting the PS1/*PS2 switches correctly changes the diagnostics on your DP/DP coupler.

Hope this helps,

Daniel Chartier

Hi 

It changed but not much, only how power supply is present

So, initial

Diag_01 = 00         Status_01 = 09

Diag_02 = 0C        Status_02 = 81

Diag_03 = 00         Status_03 = 00

Diag_04 = 02         Status_04 = 00

Diag_05 = 80         Status_05 = 01

Diag_06 = 70         Status_06 = 20

Diag_07 = 43         Status_07 = E0

Diag_08 = 00         Status_08 = 14

Diag_09 = 00         Status_09 = 01

Diag_10 = 08        

Diag_11 = 82         

After setting SIL switch PS to DP2 = ON, si DP1 = OFF Status_09 became 00, understand DP/DP knows it is supplied from both networks. ( Which is not actually )

I am using diagnostics over CPU2, where I have original program source as well as direct access.

Repeating this on CPU1 it is harder. Not impossible, just a little more difficult. Probably will do next time when it will stop. However I instructed operator not to reset DP/DP coupler anymore and try to find a better solution for reset.

pim