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+--- Thread: limits when LM as Modbus TCP slave (/showthread.php?tid=3015)
limits when LM as Modbus TCP slave - ikhy - 25.11.2020
Thanks a lot for the LM resident script like Modbus TCP slave! We can use 125 registers at a time, right? what can i do if i need to read / write more registers? what are the limitations in this?
RE: limits when LM as Modbus TCP slave - admin - 25.11.2020
125 registers is ModBus standard limit. But it only applies to a single request. If you want to read/write more then send several requests.
RE: limits when LM as Modbus TCP slave - ikhy - 25.11.2020
(25.11.2020, 10:22)admin Wrote: 125 registers is ModBus standard limit. But it only applies to a single request. If you want to read/write more then send several requests.thanks! but what about addressing with multiple requests? will the address of the first register in the second request be 0 again? oh, understand
addressing continues
RE: limits when LM as Modbus TCP slave - admin - 25.11.2020
Each read request has a starting address and a number of coils/registers to read. The starting address is an absolute value and it does not matter which address was used in previous request.
RE: limits when LM as Modbus TCP slave - ikhy - 25.11.2020
so no limits? 65536 registers can be polled?
RE: limits when LM as Modbus TCP slave - admin - 25.11.2020
Yes, the whole range can be used.
RE: limits when LM as Modbus TCP slave - ikhy - 25.11.2020
thank you!