Xylem System 5000 User Manual - Manual (Page 88)

MODBUS
86
The following definition should help in choosing which options to use:
The Modbus Master I/O should be used when the System 5000
™
is expected to initiate
communication with other Modbus Slave devices on the network. Modbus Master Input
indicates a value will be read from a Modbus Slave, whereas Modbus Master Output
indicates a value will be written to a Modbus Slave.
The Modbus Slave I/O should be used when an external Modbus Master will be initiating
communication with the System 5000
™
, expecting a Modbus Slave. Modbus Slave Input
defines a virtual register that expects to be written by a Modbus Master, whereas Modbus
Slave Output defines a virtual register that expects to be read by a Modbus Master.
As Modbus Slave devices await requests from Modbus Masters, the System 5000
™
Modbus
Slave setups can also be viewed and configured within the Listening Ports Setup menu of the
System Setup - Communications tab.
Creating a New Port
Modbus can communicate on any
serial or network port available on the
System 5000
™
. In order to do so, a
port needs to be set up first. Within the
Select Input and Add Output menus,
the Modbus Master/Slave (New Port)
will automatically assign a new port to
be used with Modbus. The port and
settings can be further configured on
the Modbus Properties screen after
the OK button is pressed.