Destination node number, if set to default this is the subnet byte of the ip of the plc (ex. 192.168.0.1 -> 0x01)
Destination unit number, the unit number, see the hw config of plc, generally 0x00
Destination network address, 0x0 local , 0x01 if there are not network intermediaries
Information Control Field, set to 0x80
Main command code (high byte)
Source node number, like the destination node number, you could set a fixed number into plc config
Source unit number, like the destination unit number
Counter for the resend, generally 0x00
Source network, generally 0x01
Sub request code