Post by gilbert-mh on CAA net base TCP client cause PLC to crash - Kernel message : N0HZ_local_softirq_pending 80 ^{CODESYS Forge talk (Post)}
Hello all, I have been trying to implement a TCP client on a Festo PLC (CPX-E-CEC-M1) and it looks like it works well except that after some time (greatly varies between a few hours to more than 100h) my PLC crash. When I look into the log file the only thing I see is that before the crash happens a few kernel warnings : N0HZ_local_softirq_pending 80 and then the crash. I've looked into this warning and from what I could find on the net it seems that this is warning is triggered when the ethernet link is down. I've tried to correct this bug for quite some time and what I know is that : - The crash is caused by my TCP client, when I remove it from my code I see no crash - The crash happens more quickly the more the TCP client is used. - The time before the crash is not directly proportional to the number of communications or their size. But it looks like it is just more likely to happen if the client connect to the server at a higher frequency. - The precedent observation makes it seem unlikely that the crash is caused by some memory overflow because then the crash speed would be more proportional to the amount of data exchanged. SO from these observations, I believe that the crash could be caused by the PLC trying to connect to a server while there is some kind of issue with the ethernet link resulting in the PLC getting stuck in some indefinite state and making it crash. This still seems a bit unlikely to me because if the ethernet is down it simply shouldn't be able to contact the server and the communication would just fail which doesn't cause my PLC to crash. Has anyone encountered the same kind of problem (with the same kernel message) ? I am pretty sure the warning is not the direct cause of the crash but just an indicator that something is wrong with my PLC. Thanks in advance
Last updated: 2024-01-12

Post by ofey on EtherCAT fieldbus ^{CODESYS Forge talk (Post)}
Hi, everyone! I'm trying to set up a PLC controller and a connection to an EtherCAT slave device in Codesys. I want to create a flexible program that I can upload to multiple controllers with different remote IO connected (same program). On one plant i may have 5 AI-cards and 3 DO-cards, and on another I may have 4 AI-cards and 2 DO-cards. For not needing to maintain several different programs wih different devices defined in the program (one for each set up) I thought that using a remote IO would make it easier having a single program. That way I could refer to different memory addresses instead of predefined slots/channels and IO's, that would give me errors if there was a different IO on the plant than what the program expected. When I tried setting up the etherCAT master, I saw that I had to define the etherCAT slave devices with the different IO'cards for me to be able to refer to the memory addresses in a PRG. Exactly what I was trying to avoid. My setup is something like a program that can handle 16 separate pump controls. In a year maybe 6 plans get deployed, and depending on how large the project is, the number of pumps can vary between 4 and 16. And the managers dont want to have IO's for all 16 pumps on every cabinet, and I dont want to maintain 16 separate projects files in case of updates etc. I thought the best way to tackle this was having a single project that read/write data to the different pump IO's by remote IO (fieldbus ethercat) addresses. And the number of pump controls are activated by an external GUI. If pump 1-6 is activated by the GUI, then the PLC-program tries to read/write input/outputs from predefined addresses for the expected IO's. My test setup is a PFC200 WAGO controller and a EtherCAT fieldbus coupler (750-354) with some IO. I hope I didn't explain this too horrible, and if there is a more easy and elegant solution for this challenge I appreciate a feedback on this.
Last updated: 2024-04-08

Post by greenwood on CODESYS Control Raspberry Pi mit Servotreiber T6 von StepperOnline ^{CODESYS Forge talk (Post)}
Hallo, ich versuche, eine Modbus-RTU-Kommunikation zwischen meinem Raspberry Pi mit CODESYS Control für Raspberry Pi 64 SL und einem Servotreiber von StepperOnline, Typ T6, herzustellen. Die Verbindung ist wie folgt: RJ45-Stecker am Servotreiber -> Kabel mit RJ45 an einem Ende und USB-A-Stecker am anderen Ende -> Seriell-zu-USB-Konverter -> Raspberry Pi. Der Seriell-zu-USB-Konverter und die Kabel habe ich zusammen mit dem Motor und Treiber von StepperOnline gekauft und sie sind dafür gedacht, den Servotreiber mit einem Computer zu verbinden, auf dem deren Setup-Software läuft. dmesg | grep tty auf dem Pi sagt mir, dass der USB-zu-Seriell-Konverter auf ttyusb0 ist. Ich weiß nicht, wie man das in einen COM-Port übersetzt, ich habe COM 1 genommen. Ich habe ein Projekt in Codesys erstellt und ein Modbus_COM-Gerät hinzugefügt, einen Modbus_Master_COM_Port und einen Modbus_Slave_COM_Port angehängt. Auf der Registerkarte "Allgemein" des Modbus_COM habe ich die folgenden Werte eingestellt: Slave address 1 Baud rate 9600 Parity None Data bits 8 Stop bits 2 Ich habe den Servotreiber auf die gleichen Werte eingestellt. (Ich habe auch andere Werte getestet, aber mit dem gleichen Ergebnis). Auf der Registerkarte "Modbus Slave Channel" des Modbus_Slave_COM_Port habe ich einen Kanal hinzugefügt und die folgenden Werte eingetragen: Access type Read Holding Registers (Function Code 3) Read Register offset 0x0000 Length 1 Ich habe noch keinen Code geschrieben, weil ich noch nicht herausgefunden habe, wie man die Kommunikation programmiert. Wenn ich das Projekt zum Raspberry Pi herunterlade scheint der Modbus_Master_COM_Port zu laufen (grünes Symbol), aber der Modbus_Slave_COM_Port nicht (rotes Dreiecksymbol). Wenn ich einen anderen COM-Port eintrage, haben sowohl der Master als auch der Slave das rote Dreiecksymbol. Ich habe dies auch mit meinem Windows-PC unter Verwendung von Codesys Control Win 64 versucht und die gleichen Ergebnisse bekommen. Ich wäre dankbar für jede Hilfe oder Tipps, wie ich den Grund dafür herausfinden kann, warum der Servotreiberreiber nicht reagiert.
Last updated: 2024-05-31

Post by george32 on CSV file and string manipulation. ^{CODESYS Forge talk (Post)}
Dear folks, I think I have a rather simple question but I could not find the right answer to my question: I have made with Excel a CSV file where I would like to have some general data regarding my program variables. I have made an program what let me read the file. The string I am currently get is at follows: 'IP_Adres;192.168.45.12$R$NPort_number;2000$R$NCycle_time;43$R$NStart_Standard_IO;20$R$N' Now I want to split the string in multiple part, which I later would connect to the right variable. By Google and experimenting I have reached to the following code for the first part of the splitting proces: // Splitting the BOM of the string: Received_string := FileReadString; IF LEFT(STR:=New_string,3)= '' THEN Received_string_without_BOM :=RIGHT(STR:= Received_string,SIZE:= (LEN(STR:= Received_string))-3); END_IF //Splitting the remaining string in part for later declaration. WHILE index = 0 DO index_split_part := FIND(STR1:= Received_string_without_BOM,STR2:= '$R$N'); Part_of_String[index]:=LEFT(STR:=Received_string_without_BOM, SIZE:= index_split_part); index := index + 1; END_WHILE However in the splitting proces I could not understand what is really happening. I understand that the Find() function returns the first value the $R$N in the Received_string_without_BOM. This would mean that the index_split_part := 23 I|P| _ |A |d|r|e|s|;|1_|9 |2 |. |1 |6 |8 |. |4 |5 |. |1 |2 |$ |R |$ |N |P | 1|2| 3 |4 |5|6|7|0|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27| So the next part is to read the first 23 characters of the Received_string_without_BOM with the LEFT() function. I expected that the outcome the following was: 'IP_Adres;192.168.45.12$'. However the outcome is: 'IP_Adres;192.168.45.12$R'. I do not understand where the R after the $ sign comes from, because its place is 24 so it would not be added to the part_of the_string[index]. If I hard coded value 24 for the size it gives me the following return: 'IP_Adres;192.168.45.12$R$N'. I would expect everything till the R but the code adds the $N also to the string. I hope someone could explain to my what I am seeing wrong in my point of view? With kind regards, George
Last updated: 2024-09-27

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