How to read memory words of M172 via ModbusTCP

It is possible to read the system words and status variables of the M172 / M172 PLC via ModbusTCP.

Make sure that the Ethernet port is enable in the PLC bios settings.

M171 and M172 PLC's use one based addressing so make sure the system that will be reading / writing to the M171 / M172 PLC supports one based addressing.
If one based addressing is not supported then remember to shift the resgister you will to access by minus one.

For example:  The first "Status Varaible" of M171 / M172 PLC's is at address 8960.  For 1 based address you will access this register at address 8960.  If using 0 based addressing you must access this register at address 8959.

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