Post by xcqt on Oop best practice ^{CODESYS Forge talk (Post)}
Hi all, I’m currently trying to improve my OOP structure in CODESYS and I’m looking for some input on how others approach this. I understand the basics like inheritance, interfaces, abstract FBs, methods, and properties, but I still struggle a bit with the overall architecture and what’s considered clean or scalable in bigger projects. As an example, I’m working on two different energy meter function blocks: FB_EnergyMeter_MQTT reads data from MQTT (strings) FB_EnergyMeter_Modbus reads data from Modbus (words) Both have their own Update() method and implement the same interface (something like IF_EnergyMeter). Later on, I’ll probably add more meter types, but they should all behave the same from the controller’s point of view. Now, there’s a FB_GridControl block that needs power data from these meters. I see two options here: Define the meter blocks inside FB_GridControl and call them directly (for example fbModbusMeter.UpdateModbus()). Keep the meter blocks outside and pass them into FB_GridControl as interface references, so the control block doesn’t know which specific type of meter it’s dealing with. Option 2 feels cleaner and more flexible to me, but I’m not entirely sure how to handle the data flow in that case. Should I pass the meter instance through an interface reference (REFERENCE TO IF_EnergyMeter)? Or is there a better way to link the external FBs to the control block? I’d like to hear how you structure this kind of setup or see an example from someone who has done something similar. EDIT: I think i need to do something like this fbModbusUpdateInput(wInput:= wWordValue); fbMqttUpdateInput(strInput:= strStringValue); IF bUseMqtt THEN Meter REF = fbMqttUpdateInput; ELSE Meter REF = fbModbusUpdateInput; END_IF fbControl.SetMeter(UsedMeter := Meter); Or am i thinking wrong? Thanks, Thomas
Last updated: 2025-10-16

Post by george32 on Readable IO names ^{CODESYS Forge talk (Post)}
Hello Folks, I have a quite basic understanding of how PLC programming works. However I keep getting stuck on 1 problem I could not get my head around. The problem is as follow: I have a PLC with 60 IO (20 inputs, 40 outputs). Each IO is defined as a function block. Furthermore I have an external IO card connected trough a CanBus connection. This IO card has 4 analog input channels (USINT), 4 digital inputs (Bool) and 4, digital outputs (Bool) Because I have 2 different components which both has data have I made 4 arrays to store the data off every component in one variable. PLC_Input: Array [1..20] of BOOL; PLC_Output: Array [1..40] of BOOL IOCard_Input: Array [1..8] of BOOL IOCard_Output: Array [1..4] of BOOL Because the control and reading of the different in and outputs is done by a TCP connection I want to use some kind of enumeration or struct to give each index a name so that my main would be a little bit more readable instead of all the magic numbers. Also this would make my program more dynamic for the furter in case I need to changes some in the IO nummers. For example: pump is placed on the fysical terminal strip number place 54, which is the 3th output of the IO card in the program: if I am sending a message with value 54 I would like to control IOCard_Output[3]. If there is a solution or methode to get this done, I can eventually do the following in my main program: IOCard_Output[Pump]. I have tried the following: IOCard_Output[Pump - 51] with an enumration but this keeps raising an error I hope some of you could help me further with this problem. In gross lines: I want to couple all the different IO to a more readable name and this readable name should control the right Array index Thanks in advance, George
Last updated: 2024-09-26

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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