Hello Guys,

I am having issues with communication between 2 master PLCs (S1200 and S300) that are mutually connected via DP/DP coupler. Even thus there are no BF active on any device, there is no communication between them, because I have one small HMI screen attached to one of those PLCs that is showing live counter that should go from 0 to 64000. I took SW backup of both PLCs and when I was going through the code, I believe I noticed something strange. Input and output addresses are different for Master PLC 1 in respect to Master PLC 2. In attachment I am sending you picture with addressing of DP/DP coupler. Can you please advise if this can even work or I am interpreting something wrong? I have very little experience with S1200, so I am not sure about this.

I would appreciate any help and suggestions!

Hello Duris,

thank you very much for your reply. In attachment I am sending HW configuration of second master PLC for DP/DP coupler. Sorry I didn't include it the first time. Essentially yes, intention of the project is to exchange signals between both master PLCs. For example live counter signal is sent from one master PLC to another one, then that PLC will increment number by one and return it to second master PLC, that is how they designed alarm to appear if communication stops. But other than that, ll these signal are not exchanged because one master PLC cannot see position of other equipment because it is getting that data from another master PLC. I scanned profibus network with profitracer and there are definitely no issues with cables, connectors etc.

Based on this second screenshot from Coupler addresses from HW config, do you think this data can still be exchanged or is this a culprit?

Thank you for the help in advance!

TommyTommy123456

Hello Duris,

thank you very much for your reply. In attachment I am sending HW configuration of second master PLC for DP/DP coupler. Sorry I didn't include it the first time. Essentially yes, intention of the project is to exchange signals between both master PLCs. For example live counter signal is sent from one master PLC to another one, then that PLC will increment number by one and return it to second master PLC, that is how they designed alarm to appear if communication stops. But other than that, ll these signal are not exchanged because one master PLC cannot see position of other equipment because it is getting that data from another master PLC. I scanned profibus network with profitracer and there are definitely no issues with cables, connectors etc.

Based on this second screenshot from Coupler addresses from HW config, do you think this data can still be exchanged or is this a culprit?

Thank you for the help in advance!

 Your coupler I/O area setup is ok on both PLC's. So both PLC's are informing you that there is no problems in the Coupler? If so, the you must have some kind of error in the code itself.

Hello Hati,

thank you for the feedback. Yes, that is correct there are no errors present on these two PLCs and that was also strange to me. However, I taught that on S1200 CPU I/O area input and output addresses have to match S300 CPU I/O area for DP coupler? For example signal "Live Counter" has Q address 18..19 on S1200 side and I address 70..71 on another side. I taught these addresses have to be the same? I connected to S300 CPU today and in fact I couldn't see any data from S1200 coming in when I was monitoring value. I was toggling one switch on/off to see any response, but didn't get any..

TommyTommy123456

Hello Hati,

thank you for the feedback. Yes, that is correct there are no errors present on these two PLCs and that was also strange to me. However, I taught that on S1200 CPU I/O area input and output addresses have to match S300 CPU I/O area for DP coupler? For example signal "Live Counter" has Q address 18..19 on S1200 side and I address 70..71 on another side. I taught these addresses have to be the same? I connected to S300 CPU today and in fact I couldn't see any data from S1200 coming in when I was monitoring value. I was toggling one switch on/off to see any response, but didn't get any..

 Both masters have their own I/O area, they don't need to match. That is the whole idea of the Coupler.

How are the DIP switches set in the coupler? Can you show us the config of the couplers?

Hello,

sorry I didn't include that detail. Switch I toggled is digital input signal (Zms.zmsovveriden). This switch is attached to S300 PLC. I was toggling switch, and waiting for that signal value to change in live monitor view, but as I wrote it never changed. And remaining signals are not changing any values. I attached part of the code that defines how is data being moved. If I can provide any other details please let me know.

Thank you very much for help and support!

Hello Hati,

thank you for the clarification, now I believe I start understanding this little bit better. I have very little experience when it comes to DP/DP couplers, didn't have any issues until now. 

How are the DIP switches set in the coupler? Can you show us the config of the couplers?

Where can I locate this configuration? 

This is configuration that I have if that is what you mean:

CPU 1212C Profibus Interface:Address 1

Slave S200 Profibus Interface:Address 3

DP/DP Coupler Network 1 Side:Address 4

DP/DP Coupler Network 2 Side:Address 16

CPU S300 Master PLC: Address 1

Slave I/O rack: Address 3

TommyTommy123456

Hello Hati,

thank you for the clarification, now I believe I start understanding this little bit better. I have very little experience when it comes to DP/DP couplers, didn't have any issues until now. 

How are the DIP switches set in the coupler? Can you show us the config of the couplers?

Where can I locate this configuration? 

This is configuration that I have if that is what you mean:

CPU 1212C Profibus Interface:Address 1

Slave S200 Profibus Interface:Address 3

DP/DP Coupler Network 1 Side:Address 4

DP/DP Coupler Network 2 Side:Address 16

CPU S300 Master PLC: Address 1

Slave I/O rack: Address 3

 You have a fault in the code is you expect to have a change in the live counter, since you are writing the bool value to the next word, that is not live counter.

The Coupler has dip switches for certain setup functions. Then you can do parametrization on the HW config of the Coupler also. We really don't care a bout the DP addresses, since your network doesn't have errors.

Dear Duris,

Yes I will do that first thing tomorrow morning as I had to leave the sight. Bellow I will attach picture of current setup, I apologize but it is not the prettiest one at the moment, just something I created/ modified on the go. Yes I have the manual regarding dip switch setting for addressing etc. I believe that is the correct setup, because those addresses are also shown in my profibus tester.

Thank you again for help and support!

Dear Hati,

can you please explain or highlight where is that fault in the code regarding this you wrote? 

"You have a fault in the code is you expect to have a change in the live counter, since you are writing the bool value to the next word, that is not live counter." What should I rectify then? 

Hello Duris,

today I did just as you advised and that actually helped a lot! SO I forced values in VAT tables and actually now I see that addresses and communication between two master PLCs is not an issue. There is variable IW500 that should actually send that counter signal to the master PLC on one network and then that should go to another master PLC on the second network, but it is not doing that.. So right now, I believe I have an issue on slave PLC in network 1 (S200) that should generate that counter signal. However, today I also notices some faults in TIA portal regarding S1200 PLC. Looks like device or I/O error with message "error in lower level component". In attachment I have several pictures of tests as well as that error. Unfortunately for S200 I need to use MicroWin to see what is happening and that is not my strong side.. Do you have any suggestions I can try to locate that error or? Somewhere on the forum I saw that doing extended download to device helps.

TommyTommy123456

Hello Duris,

today I did just as you advised and that actually helped a lot! SO I forced values in VAT tables and actually now I see that addresses and communication between two master PLCs is not an issue. There is variable IW500 that should actually send that counter signal to the master PLC on one network and then that should go to another master PLC on the second network, but it is not doing that.. So right now, I believe I have an issue on slave PLC in network 1 (S200) that should generate that counter signal. However, today I also notices some faults in TIA portal regarding S1200 PLC. Looks like device or I/O error with message "error in lower level component". In attachment I have several pictures of tests as well as that error. Unfortunately for S200 I need to use MicroWin to see what is happening and that is not my strong side.. Do you have any suggestions I can try to locate that error or? Somewhere on the forum I saw that doing extended download to device helps.

 Looking at your pictures, Profibus1 has no connection. Check the 1200 PLC diagnostics buffer to see the fault.

Hi Duris,

so I took some pictured of diagnostic buffer for those 2 profibus devices (ACS rack being S200 PLC) and DP/DP coupler. When I open diagnostic buffer, all the fields are greyed-out. So just to put a bit of a perspective, S1200 CPU failed and that was changed, SW was loaded on CPU and ever since then it is not working. So now I am wondering is there any incompatibility between modules in the system, or something is not configured correctly? I have latest version of the program, but when I attempt to go online it says incompatible. But when I create new project and load software from PLC it is fine, with exception of those faults appearing for profibus modules (previously attached pictures). Yes, profibus network, connectors, terminating resistors are all good, no BF or SF red lights turned on or anything similar. Yes, there is EM277 PB Slave module attached to S200 and then it connects to the rest of the network. I am also bit confused because I was expecting some issue with DP/DP coupler, but data can go in both directions, but in my opinion it looks like S200 slave is not sending data to S1200, or S1200 cannot receive data from S200, what do you think? Also since CM1243-5 PB module was replaced I am wondering, could bad FW version of that module cause all these issues? I am asking because if data can be exchanged between 2 master PLCs on the network than it shouldn't cause all these issues?

Hello Duris,

thank you for guidance and help. I already verified that all PB addresses are set up correctly on devices (dip switches and rotary knobs) and they are matching addresses defined in software on master PLCs. I also hoped that would be the issue, because that would be" relatively easy to fix". I will investigate further in S200 with MicroWin and will keep you guys posted.

Hello Hati,

bellow is attached that picture. This fault happened when I was disconnecting profibus cable to check if wiring is okay and latest ones is just warning that values have been forced (from the test I did yesterday). The only thing that I am not sure at this stage is, why do I have those errors (exclamation marks and message error on lower level component). Is it because something is not configured properly in S1200 or is it because data is not "coming" from S200?

TommyTommy123456

Hello Hati,

bellow is attached that picture. This fault happened when I was disconnecting profibus cable to check if wiring is okay and latest ones is just warning that values have been forced (from the test I did yesterday). The only thing that I am not sure at this stage is, why do I have those errors (exclamation marks and message error on lower level component). Is it because something is not configured properly in S1200 or is it because data is not "coming" from S200?

 If the 1200 can't read from the 200, you would have an I/O access error for that I/O area.

Hello,

only for sure, check on TIA you have not still enabled Force value function, it can be still enabled. From very long time I remember something similar with this kind of error, check that carefully on all defined Online tables. Am I good understand, you said you have that disconnect and read error when you disconnect PB cable so after you have cable connected, all is ok only that Low level component is there?

Hello Hati,

I understand now. Thank you for explanation. So it looks like I/O blocks are defined correctly, but S200 is not "generating" signals that I would expect, need. And 1200 is reading those block with values that are not moving. And that actually makes sense, because even small HMI screen that is attached to PLC is not seeing any values, just fields with values 0. So that probably means, something is either wrong with the code in S200 or there is a condition set for program to start. What do you think?

Hello Duris,

sorry for poor explanation.. Yes, I double checked that I don't have any force value anymore (in the tables and by LEDs on PLC). Yes that is correct, those low level component errors are still present with everything connected back to original. And error came when I disconnected PB cable with intention to verify cabling. As Hati is saying, everything seems to be "wired and connected" correctly in HW and SW but still no data exchanging between S1200 and another master PLC on second network.

Hello,

look again to my first post at page 2 up, there I ask you simply that we need to know where that actual data comming from, to be sure why there we see are 0. Look again, you can't have data changed between PLC1 and PLC2 via coupler because data are 0, not cahnged as I've mentioned there. Therefore I ask you to maybe force on that addresses value to see efect on partner side - check VAT. You can easy f.ex. remark some process on PLC to not start something wrong but you need to know if you can do that.

Hello Duris,

I am not sure if I actually understand what you are suggesting. I tried forcing values from S1200 PLC to S300 and values are there. And values from S300 are coming to S1200. I will attached test pictures again. Data from S1200 going to S300 is in fact 0 unless I force value in from S1200 PLC. And I did that as you described using VAT/ Force tables. At this stage, I believe data is coming from S200 PLC (but in fact it doesn't) and goes to S300 (master on network 2). Unfortunately I cannot connect to that S200 with PPI cable for some reason it cannot detect device, and I have another system with identical CPU and I can connect and read without any issues, not sure if that can be related to this communication issue or not..

Hello,

ok, no problem. So I understand now your situation that test of exchaneg of data between S7-1200 and S7-300 via Coupler are ok, as I've sugested to you to do, perfect, but if you did forced some test values, correct? Ok, so you have only problem with S7-200 connection to S7-1200. With PPI and CPU226 (hope I see that correct) you can use for comm service also second PPI port on CPU and try better put to stop that CPU, if you can. I don't know if your S7-200 can be set to STOP but do that and then try connect via second PPI port. If this fails, you can maybe deattach PB cable from EM277 and try connect via this PB port, but I'm quite not sure if you can be lucky but try that. I see you've be lucky with connection to other S7-200 cpu so I expect yo understand what is needed to set in PG/PC interface. Hope your S7-200 isn't damaged, can you put it to RUN/STOP with correct LED indication? What exactly PPI adapter you have, order number?

Hello Duris,

unfortunately I cannot stop the cpu or connect to PB attached on Em227 module because I have plant running. I tried few more thing and both ports on it and without any success. I am wondering if I have issues with the CPU module.. Model number for USB/PPI cable is 6ES7 901-3DB30-0XA0. 

Hello,

good information. Ok, it looks then that S7-200 is ok and working but as previously sugested S7-1200 is maybe not correctly configured? For your Microwin connection via Adapter, it looks to me like problem with no correct set of comm properties due Microwin and PLC, inside PG/PC interface. Try look to our S&-200 HW Conference or try find something depended to connection problems to S7-200 CPU. Hope is not some China CPU where problem can be with language settings, really this problematic is huge. Try set on PG/PC interface (with your PPI adapter set to PPI protocol) but at upper side set Microwin Access no Step7 Online because that is for Step7. You can also try directly inside Microwin click on left to PG/PC interface what is better in my opinion, you need find correct speed for existing CPU's ports, here I expect maybe 9600 speed so only can give you this info, you need find solution. No problem to other help.