Renu Electronics GWY-500, Руководство пользователя

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GWY-500-B Features
Doc No: UMAN\GWY-500-B\0106
REVISION 4
25
4.1.2 Master-Slave Configuration
In this mode, one of the Gateway ports is a master and other is the slave so the devices connected on these ports are
slave and master respectively. Blocks do not control data transfer in this mode. Data transfer takes place only when
Master Device, connected on slave port of Gateway, sends a request to read / write data. This mode requires mapping
registers for data transfer. Mapping means defining one or multiple registers in the Slave Device corresponding to one or
multiple registers / coils in the Master Device. Mapping can be done using the Block definition area, so in this mode, any
Block is used for mapping registers of the two devices.
In Block Definition area, # Words Field indicates number of registers to be mapped linearly from the starting addresses
of the Source Device to the Destination Device. Maximum number of registers that can be mapped is 255, but this does
not mean that Master Device has to read / write 255 registers in one command.
In one command Master can read / write registers from one Block only, so if multiple registers are to be read /
written using a single command, # Words also limits the maximum number of registers to be read / written. Number of
registers to be read /written in one command also depends on
- protocol of BOTH the devices
- Buffer capacity of Gateway.
Now let us take the example of Master-Slave mode.
Configure Gateway ports as: PLC1 Protocol - Modbus (Gateway as Slave)
PLC2 Protocol - Profibus.