Specifications

Level One: Protege GX Installer Study Guide | August 2013 187
The Download Service is advised of a successful download by the controller. The controller sends this message
to the Download Service via the Event Service and Data Service.
Download
Service
Event
Service
DVR
S
ervice
s
Data
Service
Controller(s)
DVR/NVR
(
s
)
)
When the server successfully sends a new configuration to the controller, it writes a file to its local hard disk.
This file contains only the current configuration of the controller.
Download
Service
E
v
e
n
t
S
ervice
DV
R
Service
s
Data
Service
Event
t
D
a
t
abase
G
X
D
a
t
abase
DAT file(s)
If the Event Service is not working, the Download Service will never receive the message from the controller to
say the download was successful and the DAT file will not be saved. This will result in the Download Service
continuing to attempt a download to the controller.
The period that the Download Service compares the configurations is defined by the Download Retry Delay
setting found under the Configuration tab of the Controller properties. By default, this is set to 60 seconds and
means that when you make a change to the GX database using the client, it may take up to 60 seconds before
the server starts to download the configuration. Depending on the type of controller you have, it can take
another 5-60 seconds before the changes take effect.
The Download Retry Delay should only be shortened while configuring a new controller. This allows
configuration changes to be pushed out more frequently. Once the configuration is complete, the delay should
be set back to the default of 60 seconds. This is especially important on systems with a large number of
controllers, or on systems using higher cost data links to communicate with controllers. Using a larger delay and
manually triggering a download when configuration changes are complete will mean less data is used.
The Download Service should be stopped when restoring a database and only restarted once you have
checked that the configuration of the newly restored database is correct. The Download Service will then push
out any configuration changes to the controllers.
By default the Download Service uses an outgoing port of 21000 for configuration and firmware downloads, and
outgoing port of 21001 for status requests and control messages.