Chapter Two
Operation
MAN_105G_1.5
Page
14
Chapter 2
OPERATION
2.1
Start-up
The 105G 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 105G 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 105G I/O database registers. The 105G 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 105G 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 105G provides an "Active" signal on the RS232 port (DCD pin 1). Its
purpose is to indicate to the host that the 105G is now processing output messages for the
remote modules. When the 105G powers down (or should an internal fault occur), the
"Active" signal resets (turn “off” or “0”). When the 105G 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 105G database, then the “active”
signal will be held in the reset state for 100 seconds (20 x 5). During this period, the 105G
will not change any output values in its database. After this time, the 105G will set the
"Active" signal (to “on” or “1”) - the host can then send messages to the 105G to update the
output values in the database.
2.2
Operation
The 105G 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
data bus port. The host device can change values in the database via the data bus, and the
105G 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 data bus.
The 105G operation must be configured before the 105G will function. Configuration is
achieved by creating a configuration file on a PC and downloading this file to the 105G. The
105G configuration may also be "uploaded" to a PC for viewing and modification. For more
information, refer to the
Configuration
section of this document.
Each I/O register in the 105G database has a 16-bit value. It doesn’t matter if the remote I/O
is digital (discrete), analogue or pulse. The host protocol driver in the 105G will convert the
16 bit value into a value that the host will understand. For example, if the host device
