Post by fleaplc on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
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Did you check the communication with a sniffer ? (ex. Wireshark) to check if the holding get to zero by a wrong writing (client initialization?) o something else?
Last updated: 2026-01-27
Post by risele on Modbus connection via Qronox PCD3 M6893
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First, if you don't need to change conversion rules in runtime, take a look at "Unit conversion" module (Application -> add object -> UnitConversion). You can specify there biderectional conversion with different units, limits and so on. Second, since MODBUS don't have "real" types but only general 16-bit registers and Real is 32-bit, generally you need a byte-was conversion Real <> two Words. Note, that depending on the devices on both sides, there are two options: Real-> Word1, Word2 or Real-> Word2, Word1, where Word1 is minor register in Modbus register pair and Word2 is major. You can use simple union: TYPE u_Real : UNION rVal:REAL; wVal:ARRAY[0..1] OF WORD; dwVAL:DWORD; //same as previous, may be easier to specify the MB register END_UNION END_TYPE and convert it as following: VAR myUnion:u_Real; rValue_TO_SEND:REAL; rValue_TO_GET:REAL; END_VAR myUnion.rVal:=rValue_TO_SEND; rValue_TO_GET:=myUnion.rVal; Note, that WORD-order should be properly set in MODBUS registers, otherwise you will get strange values. This tool is helpful: https://www.scadacore.com/tools/programming-calculators/online-hex-converter/ Alternative, you can use functions as REAL_TO_DW and DW_TO_REAL from OSCAT_BASIC, for example.
Last updated: 2026-02-19
Post by husarz17 on How change Unity-ID in TCP Modbus Slave
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I need the same issue. In my application TCP server on raspberry (codesys) should have UnitID 1. But it only works when I am requesting with UnitID 255. And my application can't work with this parameters...
Last updated: 2026-03-31
Post by nulltrace on How change Unity-ID in TCP Modbus Slave
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Hey Husarz, thanks for your Message, now i understand your Problem, also able to reproduce that. Pls. give me a Short Time to Check some stuff on this, i'll come back to this Topic with news ASAP. Greetings
Last updated: 2026-04-03
Post by nulltrace on How change Unity-ID in TCP Modbus Slave
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Hey, I also waiting for feedback from Mr. Schwellinger @eschwellinger, please send me an answer, i would appreciate it. The clue is, i know the solution, but have to check if it's allowed to share.
Last updated: 2026-04-14
Post by husarz17 on How change Unity-ID in TCP Modbus Slave
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Good to know there's a solution to this problem. I hope you'll be able to share it with me. I can't wait to hear about it.
Last updated: 2026-04-20
Post by lepewe4ka on Sysmac Studio to Codesys
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Could you send me an example? I would like to generate a data structure using XML files.
Last updated: 2023-09-20
Post by lepewe4ka on Sysmac Studio to Codesys
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Could you send me an example? I would like to generate a data structure using XML files.
Last updated: 2023-09-20
Post by vladimirsmall on Send data to USB
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Hello/ Need send some file ( for example Array of string) to USB. Which library need used for this. Thank you
Last updated: 2024-07-20
Post by damian177 on Problem with downloading OPC UA tags by Data Source Manager
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After 3 hours is some progress - please find in attachment - progress1.jpg
Last updated: 2024-09-04
Post by lsislsis on RPI Serial port connects with no errors but not data being transmitted or received
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Is there any solution because we have the same problem with other hardware?
Last updated: 2024-09-30
Post by dkugler on Reading a negative number
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why not simply converting data type UINT to INT? Then avoid negative values with ... := MAX(0 , intTest); Good luck!
Last updated: 2025-05-28
Post by levih on FbHTTPs_Get how to get data from a website and use it in codesys
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You get an array of DWORD into your receive buffer. You need to process this into usable data, before you can fit it into your DUT. I've made it work using FbWrite_ToIEC_ByRule in stead of Fb_JSON_ParseAndModify. I've attached images of the code. You receive the data into ARRAY[0..1023] OF DWORD. Then you use that array as the input for fbWrite_ToIEC_ByRule. To get the output from this you define a rule to fit the expected data structure including nesting levels. The you feed the rule into FbWrite_ToIEC_ByRule and then you can set the output to be of your DUT type.
Last updated: 2025-06-16
Post by tonyadrem on update data/tim
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Hello How to update the dates from timestamp to the actual time? THX!
Last updated: 2025-08-25
Post by tonyadrem on update data/tim
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Hello How to update the dates from timestamp to the actual time? THX!
Last updated: 2025-08-25
Post by trycyclepower on How to transfer data from DINT to Union(16 Bools) which I need to use in Few FBs
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Thanks a lot, it worked.
Last updated: 2023-12-14
Post by ph0010421 on How to transfer data from DINT to Union(16 Bools) which I need to use in Few FBs
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In the Struct, change the 'BOOL' to 'BIT'
Last updated: 2023-12-14
Post by eschwellinger on Data Transferring between 2 PLCs in a same PC
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.. this will not work on the same pc
Last updated: 2024-02-06
Post by hasangenc on DI4 USB - Transfer Data
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Hi! Did you find any solution to your problem. I'm having the same right now. Best Regards.
Last updated: 2024-02-19
Post by hasangenc on DI4 USB - Transfer Data
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Well, Hi again. I solve the problem, if anyone having the same problem, I might help. You can reach me through this platform.
Last updated: 2024-02-22
Post by egau on Git - User identification data is lost when codesys is closed
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It bothers me for sure.
Last updated: 2024-04-04
Post by nano on Persistent variable storage
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use the persistence manager. with the persistence-manager, you're abΓΆe to define how, when and where you store your data
Last updated: 2024-06-16
Post by mos89p on Data source and safety PLC
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it works only for me when i specify an IP adress in communication tab
Last updated: 2024-06-17
Post by albertovalente on How extract JSONElement containing Array data
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Hi Creator: hazarath, Have you fix the problem? because I have the same issue Thanks a lot
Last updated: 2025-11-12
Post by albertovalente on How extract JSONElement containing Array data
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Hi Creator: hazarath, Have you fix the problem? because I have the same issue Thanks a lot
Last updated: 2025-11-12
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