11/12/2020 7:01 PM | |
Posts: 7 Rating: (1) |
Hello, I am pretty much entirely new to Siemens PLCs and one of our production machines had an issue lately. Machine started acting funny and finally stopped working at all. One solid red LED (SF) and one blinking red LED (BF) on the S7-300 PLC. I checked inside the diagnostic buffer and have attached that to this post. Having a hard time figuring out what all this text means. I think it has something to do with a slave station 9 (have only a mild idea of what a slave station is). Does anyone have any idea how I could trace that back to a physical device? Please note the PLC is in STOP mode. Thanks, Maintenance Jeff Attachment501_2_red_leds.txt (229 Downloads) |
11/13/2020 1:20 AM | |
Joined: 9/27/2006 Last visit: 5/11/2024 Posts: 12257 Rating: (2666)
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Hello Jeff; This manual page for the ET 200PRO distributed I/O station, headed by a IM154-1 DP module, shows how the Profibus address is configured on that module: https://support.industry.siemens.com/cs/ww/en/view/21210852/35612389003 Since BF indicates a Bus Fault, it would be worth looking at the address that is setup on the IM 154-1 DP, and compare it to the the Profibus configuration (in HWConfig) and the diagnostic buffer entries that reference OB 86 (I/O rack fault). Also tell us if the IM 154-1 is one of the end-nodes on your network, in which case the terminator circuit shown in the link above should be set active; if not, it must be deactivated. Hope this helps, |
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11/13/2020 4:38 PM | |
Posts: 7 Rating: (1) |
OB86 is already in the PLC, that message was from when the PLC was in STOP. I have attached a new diagnostic buffer after startup in RUN mode. I think I am confusing IM 154-1 and station 8 due to their close physical proximity on the machine. Sorry about that. As for the DP addresses there are small physical switches on the interface of station 9 and station 8 that indicate what their DP slave number/station number is. I believe these switches need to match up with the programming. Looking at the diagnostic buffer now in RUN mode, I do not see any issues at all with the PLC, but please double check me. I think the next step is to find where communication fails in the Profinet with HW Config tool. Again, I have confused IM 154-1 with station 8. I believe the failure is at IM 154-1 based on HW Config tool and I will investigate that device physically further. Thanks, Maintenance Jeff Attachment501_cpu_msg.txt (195 Downloads) |
Last edited by: Maintenance Jeff at: 11/13/2020 16:39:37 |
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This contribution was helpful to1 thankful Users |
11/14/2020 6:45 PM | |
Joined: 9/27/2006 Last visit: 5/11/2024 Posts: 12257 Rating: (2666)
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Hello Jeff; I hope that the 24 hour silence from your part means that your process is now working well (or at least to your satisfaction). The ON/OFF functionnality you mention on the the Profibus cable is probably the terminating resistor switch on the Profibus connector; if it is ON, the Profibus signal can continue to the next node; if it is OFF, the signal is terminated on that node, and the transmitted signal is correctly adapted by the termination circuit to eliminate reflections on the bus. Only 2 stations on a simple bus should have their terminators ON. And these are the 2 stations at each end of the linear bus, the end-nodes. It can become more complicated with complex networks, where repeaters are used for example, but basically that is the rule. And that termination circuit is also one of the most frequent causes of Profibus network failures. See the following article for more details and important information, it could be helpful if you ever face a similar situation. Top 5 reasons your Profibus network failed Hope this helps, |
Last edited by: dchartier at: 11/14/2020 18:47:45 |
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