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RK512 Troubleshooting

Created by: Darren_T3 at: 12/1/2008 8:49 PM (7 Replies)

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12/1/2008 8:49 PM	Rate (0)
Darren_T3 Posts: 95 Rating: (10)	Greetings Forum, I am having a heck of a time troubleshooting some “NAK” communication issues with RK512. What are some best practices some of you have used to diagnose/troubleshoot your configurations? Here is some info: There does not seem to any pattern with the NAK’s. I can go for days with no problems and then I will get them for several hours straight with no apparent change in the system. The next day all is well again. My setup involves (6) different PLC’s (S7-312 2DP/ Input Card / Output Card / CP341-1) each communicating to their own partner. The programs and HW Config are identical. 3 of the PLC’s communicate through a Y-Link to a redundant S7-414H. The other 3 do the same to a different redundant S7-414H. The 315’s are set up as slaves on the 414H Profibus DP network. The PLC’s are the passive partner and the ‘other end’ is the active partner (I have no control over their hardware or program on the 'active' side– but have established a good working relationship with their tech guys in a spirit to resolve this). I am only having problems with one of the configurations (#3). The other 5 are doing great. I have confirmed the correct protocol is set up on all 6 stations. I can provide in depth configuration diagrams, data tap analysis etc. but for now I will just fly this up the flag pole and perhaps someone will present a troubleshooting idea I have not tried yet. An idea that came to me justtoday was to take the PLC hardware from #3 and swap it with one that is functioning well (#1). I was also going to ask the ‘active partner’ side to do the same (like they can swap #3 with #6) and then we can see where the issue goes. Does it stay at #3, move to #1 or show up in #6… Thanks in advance for your ideas. Once we get this resolved I will share the analysis on this post for others to find and perhaps help them out as well. Cheers, Darren
Darren_T3 Posts: 95 Rating: (10)
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12/4/2008 4:33 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Dear Darren, exchanging the Hardware first of all is a good idea. If it the problem does not move I would try to find out if there are any differences between the one link which does not work and the other links. If there is something, maybe about EMD or differing potentials. Things like that may interrupt the communication, especially if it is possible that certain changes in the System, maybe even outside the communication itself, take place. Potentials move... things like this. Have you already monitored the traffic on the RS 232 line you use? (I hopeit is a RS 232 Line you use) There arecertain monitoring tools available... maybe we could figureout some more there. Check this out: Sending and Receiving SMS Messages with S7-300/400 via serial CPs (340/341/441-2) and the GPRS/GSM Modem MD720-3 (Configuration 10) Read the chapter 8 Tips and Tricks, I think this would be very interesting. Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)
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3/31/2009 4:24 AM	Rate (0)
Darren_T3 Posts: 95 Rating: (10)	Okay, here is what we found out: The ‘active partner’ is sending the RK512 protocol to the CP341-1 as a current loop using a “Telebyte Model 65A RS-232 to Current Loop Converter” on the ‘active partner’ side. This is done due to the distance and the desire for noise immunity. According to the specifications the CP341-1 current loop card should receive the current loop signal from the ‘active partner’ just fine in this configuration but what we tried is to change out the CP341-1 current loop card to a CP 341-RS232C card and add an additional “Telebyte Model 65A RS-232 to Current Loop Converter” on the PLC side (passive side). This seemed to do the trick. So now the RK512 follows along this path: Active partner (as RS232) -> Telebyte (as current loop) -> Telebyte (as current loop) -> CP341-1 (as RS232). We have been running for over 2 months with no problems and have considered this issue resolved. Another solution we did not try (but was our plan ‘B’) is to relocate the PLC + CP341-RS232C right next to the partner thereby eliminating the need for the Telebyte since we figured it was an issue with the Telebyte that was causing all of the problems. Cheers, Darren
Darren_T3 Posts: 95 Rating: (10)
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This contribution was helpful to 2 thankful Users J_Bell Blue Moderator

5/10/2011 4:37 AM	Rate (0)
Maha Posts: 118 Rating: (4)	Hi, We have some issue on this type of communication. Here also partner using “Telebyte Model 65A RS-232 to Current Loop Converter” same like your partner. But Ourside, we are using only CP341-1BH02 Module to communicate with them, without using any telebyte 65A convertor. first point is, do we have any option to select Active partner at CP341-1BH02 (Our SIde)? they are claiming that,they set passive transmit/receive on there side. Now the status is, other partner claiming that thy are sending heart beat on DB96.But we r not getting any heart beat on that DB96. can u give some more details on wiring between CP341-1BH02(Our Side) and Telebyte 65A Convertor(Partner Side)? The wiring diagram, what they passed us has attached. I am not able to get the clear picture with this diagram too. Attachment Telebyte 65A - EDS Machine.pdf (122 Downloads)
Maha Posts: 118 Rating: (4)	Last edited by: Maha at: 5/10/2011 5:45 AM Last edited by: Maha at: 5/10/2011 5:43 AM
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5/10/2011 8:33 AM	Rate (0)
Darren_T3 Posts: 95 Rating: (10)	Hi Maha, I see you are having issues with the L3 communicating to the BHS system just as I had when I was commissioning the Buffalo, NY airport. From all the research I did this seems to be a long standing issue between L3 and the Siemens interface modules. We had to change some of the Siemens IM modules in the field at quite an expense – but it fixed all of the communication problems. I was told that L3 was expecting to update their manual with these findings but not sure if they ever did or what manual version you have (perhaps the older one that I started to commission the system with originally). I may be able to help you to clear this issue but give me a few days to dig out my notes and to identify the correct part numbers at my end. I will create a handy drawing with what I did and hopefully it is something you can work with. So stand by and I will post here once I get everything together... Cheers, Darren
Darren_T3 Posts: 95 Rating: (10)
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5/11/2011 3:10 AM	Rate (0)
Darren_T3 Posts: 95 Rating: (10)	Hi Maha, I Found all my notes so here goes: On the L3 machines I worked on I discovered a wiring discrepancy from the factory. First check to ensure you do not have the same wiring issue on your L3 machines. On the L3, In the junction box where you connect the wiring that goes to the PLC (the terminal blocks labeled K+, K-, C+, C-) the white and black wires are switched on the back of that board. (In your attached drawing this is the rectangle labeled ‘EDS PLC I/O Box) So follow along here: If you start with the wiring at the TeleByte 65A device on the L3 machine and use the following color code according to the attached sheet: C+ = BK C- = GN K+ = RD K- = WE Then if youhook up your PLC wires to the “Master PLC Discrete” terminal blocks inside the L3 junction box using the same colors than the white and black wires are switched! It turns out that the white and black wires that were soldered to the back of the terminal blocks that come down from the TeleByte were landed on the wrong points. So that is the first thing to check. Every one of my machines had this wiring error. Regarding the RK-512 handshake, heartbeat and NAK’s. The L3 manual specified what was required at the PLC side and was followed but I could never get a stable communication between the two platforms. I believe that the TeleByte 65A is somehow corrupting the RK512 protocol but I never took the time to prove it. Since the L3 guys were not going to make any changes on their end I added a TeleByte 65A at the PLC end and changed out the CP-341 card (Part number isBelow). My thinking was I would have the L3 communicate to the TeleByte 65A via RK-512 and then the TeleByte 65A on the L3 side would communicate to another TeleByte 65A on the BHS side via RS-232 and then back to the CP-341 via RK-512. That seemed to do the trick and even though there was some expense involved in buying the additional TeleBytes, CP-341 cards and Belden connection cable everything started to work as advertised. I was told that L3 was going to be changing their manual to reflect this ‘new’ configuration but I have no idea if they ever did. Looking at your attached sheet it looks like they did. I think there were also some considerations regarding who paid for what to make the communication right but that was beyond my pay grade. The CP card I switched to is the following PN: 6ES7 341-1AH02-0AE0 Wiring on the TeleByte 65A on the L3 side (Note that this is different than the wiring in the L3 junction box for my machines as I alluded to above): C+ = BK C- = GN G = x (open) K+ = RD K- = WE Wiring in the L3 junction box (You can see how the C+ and the K- wires are reversed from the TeleByte above): C+ = WE C- = GN K+ = RD K- = BK Wiring on the TeleByte 65A on the BHS side: C+ = x (open) C- = RD G = GN + BK K+ = x (open) K- = WE The cable to connect the TeleByte on BHS side to the CP-341 card pin-out is as follows (both ends are female): DSub-9 DSub-25 1 8 2 3 3 2 4 20 5 7 6 6 7 4 8 5 9 22 The attached file contains more info and screenshots on setting up the RK512 Protocol. I hope this helps you out. It took me some time to figure it all out so hopefully you have not invested too much time and this info is just in time to save you a lot of grief and banging of heads. Best Regards, Darren Koepp Attachment EDS - BHS RK512.pdf (121 Downloads)
Darren_T3 Posts: 95 Rating: (10)
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This contribution was helpful to 1 thankful Users Maha

5/16/2011 8:44 PM	Rate (0)
Maha Posts: 118 Rating: (4)	Hi Darren, Thanks for your kindful explanation, I was too busy with that Integration testing. So not able to check your message. Atlast we have done without changing any hardware with the reference from our very old project (10 years back one). still some more testing need to do..once done i will come back to you. The attachement how its working. Attachment Examienr_SerialComm_Connection.pdf (119 Downloads)
Maha Posts: 118 Rating: (4)
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9/28/2011 11:13 AM	Rate (0)
Maha Posts: 118 Rating: (4)	Hi Darren, Now the communication between PLC and L3 machine is working fine in normal life. [schnippschnapp] new question is splitted to while PLC going to stop mode and return back to run mode. the communication got break.
Maha Posts: 118 Rating: (4)	Last edited by: O_Moderator at: 9/28/2011 12:07 PM Last edited by: Maha at: 9/28/2011 11:20 AM
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