Post by tk096 on Some 'pathetic' errors in SoftMotion program ^{CODESYS Forge talk (Post)}
Meanwhile, I would like to understand why the motion FB instances must still be called even after the Execute is set to FALSE, especially in view of the fact that the next instruction is programmed to abort the previous one, with BufferMode set to 'Aborting'. All these unnecessary FB calls are an unnecessary overhead on the CPU anyway. Is there any precise rule about when to cease calling the various instances? (It should precisely be the 'done' status that says this one has finished its work). In general: - Motion function blocks have to be called until they report 'Done', 'Error', 'CommandAborted' or a subsequent motion FB with BufferMode=Aborting is started in the current cycle. - Setting the Execute input to FALSE will not abort any ongoing motion of the motion function block. For example, one case that is often problematic is the execution of the Axis Halt instruction. When, after a MoveAbosulte instruction this returns the event as 'done' and indeed the axis is in standstill, the state machine first sets the move instruction to FALSE, and the next cycle sets the Halt request to TRUE. Some of the time everything works out fine. Occasionally, however, in this exchange, the axis goes into fault, also losing the OPERATIONAL state. I think the error SMC_FB_WASNT_CALLED_DURING_MOTION is only a follow-up (and misleading) error that results from the axis not being in operational state anymore (bus problems). Is there an error 'regulator or start not set' in the device log before the error 'motion generating FB wasn't called for at least one cycle'? Which error does the respective function block (Halt.ErrorId) report?
Last updated: 2024-07-22

Post by r-niedermayer on C0564 Warning Message ^{CODESYS Forge talk (Post)}
Please see or Online Help on how to initialize variable before using them: https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_pragma_attribute_global_init_slot.html Regarding the Attribute global_init_slot: You can use this pragma to influence the order in which signatures are processed during global initialization. It can only be applied to signatures. By default, the initialization sequence for variables from global variable lists is undefined! However, if, for example, variables from one list depend on variables from another list, it is necessary to initialize one before the other. (Aee OLH and Syntax) The placeholder <slot> must be replaced by an integer value that defines the position in the initialization sequence.</slot> The default value is 50000. A lower value causes an earlier initialization! If several signatures have the same value for the 'global_init_slot' attribute, the order of their initialization remains undefined! Cautious application should therefore be considered! Example: The project contains f.e. two global variable lists GVL_1 and GVL_2. The global variable "A" is part of the global variable list GVL_1: {attribute 'global_init_slot' := '300'} VAR_GLOBAL A : INT:=1000; END_VAR The initialization values of the variables "B" and "C" of GVL_2 are dependent on the variable "A". {attribute 'global_init_slot' := '350'} VAR_GLOBAL B : INT:=A+1; C : INT:=A-1; END_VAR So if you set the 'global_init_slot' attribute of the global variable list GVL_1 to 300, i.e. to the lowest initialization value in the example, then it is ensured that the expression "A+1" is well-defined at the time of initialization of "B".
Last updated: 2024-01-30

Post by testlogic on Sending Sequential Modbus TCP Packets ^{CODESYS Forge talk (Post)}
I have a Modbus TCP slave device where I need to do sequential writes to the same register. The register I'm writing to is kind of like a command line, each packet is a command word encoded in Hexadecimal. I am having difficulty implementing this system in CoDeSys 3.5 SP19. I feel like the structure of the program should be something along the lines of (Pseudocode): ModbusTCPSend(Command Register, Command1) ModbusTCPSend(Command Register, Command2) ModbusTCPSend(Command Register, Command3) I have tried to implement this with a rising edge trigger wMot1OPCode := 16#E1; //Stop Motor & Kill Program xMot1SendOP := TRUE; //Send OP on rising edge xMot1SendOP := FALSE; //Reset wMot1OPCode := 16#9E; //Disable Motor xMot1SendOP :=TRUE; //Send OP on rising edge xMot1SendOP := FALSE; //Reset Where "wMot1OPCode" is the IO map for writing to the command register, and "xMot1SendOP" is the rising edge trigger for that modbus channel. However, this doesn't work. The device never responds to the modbus commands. It seems like the trigger variable is switched too quickly for modbus to send the packet. I know the modbus register is working, because I can set the channel to cyclic and the device will respond. However, I can't use this reliably because I need each command to be sent once, in order. Cyclic keeps re-sending the commands and seems like it could miss a command as well if one was sent in-between cycle time. I have also trying using the Application trigger as described by https://faq.codesys.com/pages/viewpage.action?pageId=24510480, but this is also not working for me. See attached picture for my FBD code. This seems like a simple function, I can't tell what I'm doing wrong here. Thanks for the help.
Last updated: 2024-03-06

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