User manual

WI-GTWY-9-xxx Wireless Gateway V1.18
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The CF Register (“comms fail” register) acts as a digital alarm – the value of the register will
normally be 0, and will be set to FFFF (hex) if the slave device does not positively respond to the
serial command within Max Retries attempts. In the examples, the same CF Register (4327 – i.e.
DOT8) has been used for both serial mappings, such that the local digital output will be activated
if the slave fails to respond to either serial command. Alternately, any other internal register
could have been chosen and mapped via radio if desired.
To complete the Fieldbus Configuration, enter any other Modbus commands that may be
required to transfer I/O points between the WI-GTWY-9-xxx and the Modbus Slave devices.
Digital I/O
The value of a digital I/O point is stored in the WI-GTWY-9-xxx database as a hexadecimal '0000'
(“off”) or hex 'FFFF' (“on”). However the WI-GTWY-9-xxx will generate either a ‘0’ (“off”) or
‘1’ (“on”) to a digital output point (Coil) when sending commands to a Modbus slave - these are
commands 05 and 15. Similarly, the WI-GTWY-9-xxx will accept ‘0’ or ‘1’ from the Modbus
slave in response to a digital read command and store ‘0000’ or ‘FFFF’ in the database location -
these commands are 01 and 02.
Analog I/O
Analog I/O from the remote WI-I/O 9-x modules are 16 bit register value. A value of 8192 (hex
2000) represents 0mA. A value of 49152 (hex C000) represents 20mA. Each mA has value of
2048 (hex 0800) - a change of 4096 (hex 1000) is equivalent to a change of 2mA. A 4-20mA