Sutron Corporation X-Link Operations & Maintenance Manual, Rev 1.63 5/24/2016 pg. 49
Scheduled:
these transmissions occur periodically, a time designated by the
user settings
Tx Time
and
Tx Interval
.
Alarm:
alarm transmissions happen when a sensor reading goes into alarm
range.
Forced:
Forced transmissions may be initiated by the user. They are used to
test a station during an installation. Additionally, a message may be sent to a
station requesting a forced transmission with specific data. SMS notification
messages are considered forced transmissions too.
5.1.1.
Scheduled Transmission Process
The basic transmission process consists of the following steps:
1.
Measurement data is read from the log and formatted into the transmission
buffer.
2.
The modem is powered on and communication to the modem is tested.
3.
Data is taken from the transmission buffer and handed to the modem. If the
station is sending a message, some data may remain in the transmission
buffer.
4.
The modem is asked to send all the data to its destination.
5.
IRIDIUMLink sends a message to the satellite.
6.
GPRSLink, HSPALink, and CDMALink setup to transmit data to a server opens
a TCP/IP connection.
7.
GPRSLink, HSPALink, and CDMALink setup for SMS messages sends a
message.
8.
If a connection is not established, X-Link will retry for
Max Tx Time
, which is
10 minutes by default.
9.
IRIDIUMLink checks for incoming messages and handles them immediately. If
a message requested a response, the response data is handed to the modem.
10.
If there is any data left in the transmission buffer, go back to step 3.
11.
GPRSLink, HSPALink, and CDMALink checks for incoming messages and
handles them immediately. If a message requested a response, the response
data is handed to the modem.
12.
Power to the modem is turned off.
