Post by abinvest579 on TCP Client ^{CODESYS Forge talk (Post)}
Hi All, I am using codesys based plc to read and control magna power DC supply over LXI protocol using SCPI command. To connect device required socket programming for that i am using Net base service library function block TCP_Client to establish connection over TCP/IP , TCP_Write to write SCPI commands and TCP_Read to read data from Magna power DC supply. I have attached screenshot for logic developed. I am able to connect and write commands to device but i not receiving any information from device. For writing Commands i also tried various end of line character like \n,<nl>, A, D, 10, 13, 0x0A, 0x0D but not received any status from device. For testing purpose i am using simple command '*IDN?' to read data. Also if tried to check on hercules software what data actually plc read, first it read correct data after that is read wrong data as see in screen shot. 'Hello World' was correct read and after that Codesys in replaced with 'Codesysorld' that is not correct way. Same issue also appeared for send data. Any one have face same issue how i can read data directly from device correctly and send data please suggest solution on this.</nl>
Last updated: 2024-07-01

Post by timvh on How to implement an interface (IElement)? ^{CODESYS Forge talk (Post)}
See: https://forge.codesys.com/prj/codesys-example/element-collect/home/Home/ This contains an application "OnlineChangeSafeLinkedListExample". What you should do is create a new interface which has your "Priority" property. Then your FB should extend the base element function block and implement your own interface: E.g. FUNCTION_BLOCK MyElement EXTENDS COL.LinkedListElementBase IMPLEMENTS I_MyInterface Then the __QUERYINTERFACE does the magic to check if your "element" also implements your interface. Something like this: // Compares this element with itfElement. // Returns 0 if the elements are equal, < 0 if the element is less than itfElement, // > 0 if the element is greater than itfElement. // This method will be called from sorted collections (e.g. |COL.SortedList|) to sort the elements. // IMPORTANT: The underlying value to be compared with MUST NOT be changed during the lifecycle of the object. METHOD ElementCompareTo : INT VAR_INPUT (* The element to compare*) itfElement : COL.IElement; END_VAR VAR itfIntElement : I_MyInterface; xResult : BOOL; END_VAR // We use integer iInt1 for sorting. xResult := __QUERYINTERFACE(itfElement, itfIntElement); IF xResult THEN IF iInt1 < itfIntElement.Priority THEN ElementCompareTo := -1; ELSIF iInt1 > itfIntElement.Priority THEN ElementCompareTo := 1; ELSE ElementCompareTo := 0; END_IF ELSE ElementCompareTo := -1; END_IF
Last updated: 2024-07-22

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 jari-koivuluoma on Problem trying Net Base Services 3.5.15.0 TCP connection ^{CODESYS Forge talk (Post)}
I have a need to send messages between 2 PLCs and I cant use network variables (because of size limit) so I tried writing this simple test program. This seems to work fine. I can send messages back and forth when a first "Start server" and then "Connect client". See the attached image. However, if I disconnect the client by setting ClientConnect to false and try to re-connect then the TCP_Client just gives me TIMEOUT error. When I stop and start the server again, then Im able to reconnect. How is this supposed to work? Why reconnecting wont work. There is not other way of disconnecting the client than setting xEnable of the TCP_Client to false. This is just a testing program and I will try it on 2 seperate devices once this works. PROGRAM PLC_PRG VAR CONSTANT mySize : UDINT := 255; END_VAR VAR Server: NBS.TCP_Server; ServerIpStr: STRING := '127.0.0.1'; ServerIP: NBS.IP_ADDR; ServerPort: UINT := 50000; ServerConnection: NBS.TCP_Connection; Client: NBS.TCP_Client; ServerRead: NBS.TCP_Read; ServerWrite: NBS.TCP_Write; ServerSend: STRING(mySize); ServerReceive: STRING(mySize); ServerConnect: BOOL; bServerSend: BOOL; IP: NBS.INADDR; ConnectedClientIP: STRING; ClientPort: UINT := 50000; ClientIpStr: STRING := '192.168.1.49'; ClientIP: NBS.IP_ADDR; ClientRead: NBS.TCP_Read; ClientWrite: NBS.TCP_Write; ClientSend: STRING(mySize); ClientReceive: STRING(mySize); ClientConnect: BOOL; bClientSend: BOOL; Error: BOOL; Message: BOOL; END_VAR // Server ServerIP.sAddr := ServerIpStr; Server( ipAddr := ServerIP, uiPort := ServerPort ); ServerConnection( xEnable := Server.xEnable, hServer := Server.hServer, ); IP := ServerConnection.IPAddress; ConnectedClientIP := F_Concat7( BYTE_TO_STRING(IP.S_un_b.s_b1),'.', BYTE_TO_STRING(IP.S_un_b.s_b2),'.', BYTE_TO_STRING(IP.S_un_b.s_b3),'.', BYTE_TO_STRING(IP.S_un_b.s_b4)); ServerRead( xEnable := ServerConnection.xActive, hConnection := ServerConnection.hConnection, szSize := SIZEOF(ServerReceive), pData := ADR(ServerReceive) ); IF ServerRead.xReady AND ServerRead.szCount > 0 THEN Message := TRUE; END_IF IF ServerRead.eError > 0 THEN Error := TRUE; END_IF ServerWrite( xExecute := ServerConnection.xActive AND bServerSend, hConnection := ServerConnection.hConnection, szSize := LEN(ServerSend)+1, pData := ADR(ServerSend) ); IF ServerWrite.xDone THEN bServerSend := FALSE; END_IF IF ServerWrite.eError > 0 THEN Error := TRUE; END_IF // Client ClientIP.sAddr := ClientIpStr; Client( xEnable := ClientConnect, ipAddr := ClientIP, uiPort := ServerPort, udiTimeOut := 10000000 ); ClientRead( xEnable := Client.xActive, hConnection := Client.hConnection, szSize := SIZEOF(ClientReceive), pData := ADR(ClientReceive) ); IF ClientRead.xReady AND ClientRead.szCount > 0 THEN Message := TRUE; END_IF IF ClientRead.eError > 0 THEN Error := TRUE; END_IF ClientWrite( xExecute := Client.xActive AND bClientSend, hConnection := Client.hConnection, szSize := LEN(ClientSend)+1, pData := ADR(ClientSend) ); IF ClientWrite.xDone THEN bClientSend := FALSE; END_IF IF ClientWrite.eError > 0 THEN Error := TRUE; END_IF
Last updated: 2024-10-03

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