WI-GTWY-9-xxx Wireless Gateway V1.18
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Chapter 2
OPERATION
2.1
Start-up
The WI-GTWY-9-xxx operating software and the database configuration are stored in non-
volatile memory; however the database I/O register values are lost on power failure (in the same
way as a PLC).
On start-up, the WI-GTWY-9-xxx sends "start-up poll" messages to remote modules based on
the source address of inputs configured in the database (the start-up messages can be disabled by
configuration). The remote modules respond with update messages for their inputs, which sets
initial values in the WI-GTWY-9-xxx I/O database registers. The WI-GTWY-9-xxx provides a
delay of 5 seconds between each start-up poll, to allow the remote module to respond and to
avoid overloading the radio channel.
If there are a lot of remote modules, then this start-up stage may take a significant time, and this
should be allowed for in the system design. The WI-GTWY-9-xxx has an internal battery
charger feature and the use of a back-up battery should be considered if this start-up delay
presents a constraint to system reliability. Start-up polls may be disabled for individual remote
modules in the database configuration.
For the host device, the WI-GTWY-9-xxx provides an "Active" signal on the RS232 port (DCD
pin 1). Its purpose is to indicate to the host that the WI-GTWY-9-xxx is now processing output
messages for the remote modules. When the WI-GTWY-9-xxx powers down (or should an
internal fault occur), the "Active" signal resets (turn “off” or “0”). When the WI-GTWY-9-xxx
starts-up, it holds the "Active" signal in a reset condition (“off” or “0”) for a time equal to the
number of remote addresses (or modules) configured times 5 seconds plus any delay if remote
addresses are offline. For example, if there are 20 remote addresses configured in the WI-
GTWY-9-xxx database, then the “active” signal will be held in the reset state for 100 seconds
(20 x 5). During this period, the WI-GTWY-9-xxx will not change any output values in its
database. After this time, the WI-GTWY-9-xxx will set the "Active" signal (to “on” or “1”) - the
host can then send messages to the WI-GTWY-9-xxx to update the output values in the database.
2.2
Operation
The WI-GTWY-9-xxx database can hold values for 4300 I/O signals plus the 8 on-board I/O.
The database registers (also called I/O registers) can be accessed by both the radio port and the
fieldbus port. The host device can change values in the database via the fieldbus, and the WI-
GTWY-9-xxx can transmit radio messages out with the new values. Radio messages can be
received with new values for database registers, and these new values can be written to the host
device or read by the host device, via the fieldbus.
The WI-GTWY-9-xxx operation must be configured before the WI-GTWY-9-xxx will function.
Configuration is achieved by creating a configuration file on a PC and downloading this file to
the WI-GTWY-9-xxx. The WI-GTWY-9-xxx configuration may also be "uploaded" to a PC for
