User manual

105G Wireless Gateway User Manual
Elpro_man_105g_1.18.doc Page 72
To complete the Fieldbus Configuration, enter any other Modbus commands that may be
required to transfer I/O points between the 105G and the Modbus Slave devices.
Digital I/O
The value of a digital I/O point is stored in the 105G database as a hexadecimal ‘0000’ (“off”) or
hex 'FFFF' (“on”). However the 105G 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 105G 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 105U 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 signal will vary
between 16384 (hex 4000) and 49152 (hex C000). A 0-20mA signal will vary between 8192 (hex
2000) and 49152 (hex C000).
Pulse I/O
Pulse counts from the remote 105U modules are shown as a 16-bit register. When the register
rolls over, from ‘FFFF’ (hex), the next value will be ‘0001’. The register will only have a value
of ‘0000’ when the remote module starts up, and the previous count is lost. This value will
indicate that the counter has reset.