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I've configured a Modbus TCP Slave underneath my ethernet adapter but can't seem to find the appropriate decimal offset to externally poll the configured registers.
Holding Registers begin at %QW0
Input Registers begin at %QW20
Coils begin at %QB80
Discrete Inputs begin at %QB82
All attempts at polling the registers result in an illegal data address exception.
Could someone please point me at the documentation describing the decimal offsets for a Codesys 3.5 Modbus TCP Slave?
Last edit: rckalex 2022-02-07
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By default, they all start at address 0, which in many clients is address 1.
The help maybe doesn't make that obvious, but the coils under data model are also under the label 'starting address'. You can find this on the general tab.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
That's what I assumed. Even though the TCP Slave shows running as soon as I start polling I still get the illegal address reply. I'll keep poking at it but I appreciate the reply!
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I've configured a Modbus TCP Slave underneath my ethernet adapter but can't seem to find the appropriate decimal offset to externally poll the configured registers.
Holding Registers begin at %QW0
Input Registers begin at %QW20
Coils begin at %QB80
Discrete Inputs begin at %QB82
All attempts at polling the registers result in an illegal data address exception.
Could someone please point me at the documentation describing the decimal offsets for a Codesys 3.5 Modbus TCP Slave?
Last edit: rckalex 2022-02-07
By default, they all start at address 0, which in many clients is address 1.
The help maybe doesn't make that obvious, but the coils under data model are also under the label 'starting address'. You can find this on the general tab.
That's what I assumed. Even though the TCP Slave shows running as soon as I start polling I still get the illegal address reply. I'll keep poking at it but I appreciate the reply!
Tripped myself up by accidentally adjusting the starting addresses in the data model field. Thanks for your help!