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CPU315-DP using ET200S Profibus errors

Created by: rustoleus at: 6/21/2009 1:48 PM (8 Replies)

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6/21/2009 1:48 PM	Rate (0)
rustoleus Posts: 3 Rating: (0)	I am having problems with my Profibus network; I have found a damaged Profibus cable but not before changing interface modules. Now that I have replaced the damaged cable and have ensured that my cabling is leaving my PLC, enters and exits nodes 1,2,3,4,5, & 6 (these addresses are for simplicity) and the HW Configuration is correct as best I know how; I have the situation where if I set the term. resistor on node 6, the HW config cannot "see" nodes 5 & 6. However, if I turn off the resistor at 6, thereby having no term resistor set in the network, HW config can now "see" nodes 5 & 6 but cannot "see" nodes 3 & 4. Please not that nodes 1 & 2 are drives within the PLC cabinet and that nodes 3 & 6 are remote 151-1AA04-0AB0 mods while nodes 4 & 5 are 151-1AA05-0AB0 mods. I have laid out new cable on the floor between nodes 2 through 6 at one point or another through out my battle with this. I have even changed out interface modules. This is the best condition that I could get my network to before taking a rest....at least I can move the problem by changing one resistor setting It must be noted that this network was up and running for a while before problem. The original condition that I found the network in is puzzling to me to say the least. The original integrators left the network with node 6 AND the cpu term resistors "on" AND with node 4's cabling reversed from what it should be.....I have NO idea how this network functioned to begin with???? Any advice would be deeply appreciated as I am gong back into work for this problem and NOT enjoying Father's day with my family
rustoleus Posts: 3 Rating: (0)
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6/21/2009 2:47 PM	Rate (0)
AMAZINGAHMED Gold Member Joined: 8/27/2006 Last visit: 10/22/2024 Posts: 719 Rating: (88)	Can you please send a drawing for your network setup?
	The more you know, The more you know that you don't know
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6/21/2009 2:48 PM	Rate (0)
Jesper Pedersen Posts: 279 Rating: (30)	Hi rustoleus. I had a similar problem the other day. Turned out that in one node at the otherend of the daisy-chain, the cable was connected at the wrong terminals. When there is only 1 cable in a connector, the cable must always go into the entry with the arrow pointing INTO the connector. With this faulty connection, the termination resistors were not active. With the termination off in the connector, everything worked - but not reliably. Some other nodes would go on and and off in a non-consistent manner. Connecting the last node in the daisy-chain in the correct way solved the problem. So, you may have to look for cabling problems at a completely different location than at the nodes that appear to be faulty. Small rant: People simply do not understand what the arrows in the connectors are about. They seem to think that it has to do with if the node is a master or a slave, or the physical location of the cable. It is simply so: 1 cable - always use the entry with arrow going into the connector. 2 cables - connect the cable from the inside part of the daisy-chain in entry with arrow going into the connector, connect the cable from thefarthest part of the daisy-chain in entry with arrow goingout ofthe connector
Jesper Pedersen Posts: 279 Rating: (30)
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6/21/2009 3:00 PM	Rate (1)
Bhaskaran Posts: 107 Rating: (13)	It seems you have the profibus cable at Slave 6 connected at the wrong side of the connector. I am not sure which Profibus connectors you have used. If you have Siemens Profibus connectors then there are arrow marks at cable entry one arrow pointing into the connector(IN) and the other pointing out of the connector(OUT). If all the stations are in single line then you should connect the cables in the following way. PLC Connect the cable at cable entry with arrow pointing into the connector. Slave 1 Connect the cable from PLC at cable entry with arrow pointing into the connector. Connect the vable to Slave 2 at cable entry with arrow pointing out of the connector. Slave 2 Connect the cable from Slave 1 at cable entry with arrow pointing into the connector. Connect the vable to Slave 3 at cable entry with arrow pointing out of the connector. Slave 3 Connect the cable from Slave 2 at cable entry with arrow pointing into the connector. Connect the vable to Slave 4 at cable entry with arrow pointing out of the connector Slave 4 Connect the cable from Slave 3 at cable entry with arrow pointing into the connector. Connect the vable to Slave 5 at cable entry with arrow pointing out of the connector Slave 5 Connect the cable from Slave 4 at cable entry with arrow pointing into the connector. Connect the vable to Slave 6 at cable entry with arrow pointing out of the connector Slave 6 Connect the cable at cable entry with arrow pointing into the connector. *The termination resistor should be switched ON only at PLC and Slave 6.* Sometimes you can also have faulty connector. Have you tried reducing the Transmission rate. Good Luck. Bhaskaran
Bhaskaran Posts: 107 Rating: (13)
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6/21/2009 3:03 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 9/26/2024 Posts: 703 Rating: (96)	Hello, you haven't mentioned what is the network topology done, e.g. a one segment line from CPU and the order of connected slaves... Only I could suggest now is to check the cables connection, whether A & B is always on the right pins andalso if the cable is connected in right order (from CPU direction to IN of the connector, then from OUT to next slave and so on). The termination should be switched-on on the end nodes (e.g. the CPU and the last slave). Also check the cable/segment minimal and maximal length and speed rules. If I had some trouble with Profibus network I would do at first the check above and if the problem lasts, make termination onall nodes and then continuously switch-off the termination on the slaves in direction from the CPU and on each change check the visible nodes (you don't need to check it in HW config, it's good enough to use the diagnose test in PG/PC interface setting). When the problem occurs, you probably have the point of trouble. Regards Sydney
	Last edited by: Sydney at: 6/21/2009 3:05 PM oops, I''''m again slow in writing :o(
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6/21/2009 4:49 PM	Rate (0)
rustoleus Posts: 3 Rating: (0)	Thank you all for replying!! You all have been a Godsend! The solution was simple from the point at which I left the network. I went to the CPU and changed the cable from outgoing to the incoming side and then turned the resistor "ON"!!!!! Problem SOLVED!!!!!! My technical support from the local Siemens distributor had given me incorrect information while he was onsite helping me. I have had extensive training and troubleshooting withAllen-Bradleyproducts but am being forced to go Siemens on new "capital" equipment. I really need to get to some classes soon, I have seen where PTO offers training on Profibus. Would they be as good or better than training through Siemens? I have one outstanding issue with this network. One cable run is going close by two moving rolls (cable is near the bearings) and also is "cable-tied" along with other conduit on a gearbox!!!! The only Profibus cable I have is Belden Profibus as I am all out of Siemens Profibus cable. Will there be any trouble if I reroute this cable run with the Belden cable?
rustoleus Posts: 3 Rating: (0)
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6/22/2009 7:53 AM	Rate (0)
Jesper Pedersen Posts: 279 Rating: (30)	rustoleus ..I am all out of Siemens Profibus cable. Will there be any trouble if I reroute this cable run with the Belden cable? If it says "Profibus" on the cable, it should be OK. That said, according to a Siemens-person I once spoke to, other manufacturers do not match the specifactions as tightly as Siemens do. If running at 12M it could result in problems. But I can tell that it wont be a problem for you. It is impossible that you are running at anything above 1.5M, and it worked partially even if there was a missing termination in one end.
Jesper Pedersen Posts: 279 Rating: (30)
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6/22/2009 9:33 AM	Rate (0)
mumbles Posts: 160 Rating: (16)	Jesper Pedersen rustoleus wrote: ..I am all out of Siemens Profibus cable. Will there be any trouble if I reroute this cable run with the Belden cable? If it says "Profibus" on the cable, it should be OK. That said, according to a Siemens-person I once spoke to, other manufacturers do not match the specifactions as tightly as Siemens do. If running at 12M it could result in problems. But I can tell that it wont be a problem for you. It is impossible that you are running at anything above 1.5M, and it worked partially even if there was a missing termination in one end. Don't believe what any salesperson tells you however I would recommend Siemens Fast Connect cabling simply because of its ease of installation and use. However, as long as the cable conforms toPTO "cable type A" specifications and the manufacturer states that 12Mb is supportedthen usingthe Belden cable will be fine. If you have the part number (which should be on the side of the cable) you can get these details from the Belden website.
mumbles Posts: 160 Rating: (16)
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6/22/2009 10:10 AM	Rate (0)
Anchobi Posts: 139 Rating: (25)	Profibus cable has the following specifications Twisted pairs Impedence 3-20MHz = 150 Ohm Capacitance < 30pF/m Loop resistance < 110 Ohm/km wire diameter > 0.64mm wire area > 0.32mm2
Anchobi Posts: 139 Rating: (25)
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