CS-3G Digital Transceiver Kits (including the COM111 modem)
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behind a router/firewall. Instead you have to get the data logger or modem
to open a connection back to either a data routing service, such as Campbell
Scientific’s Konect routing service, or a Loggernet PC which itself must
have a public IP address (see firewall issues below) and have Loggernet hold
the connection open.
1)
When using the Datalogger TCP/IP stack you can configure the logger
to automatically establish a socket connection to a remote system, e.g.
your Loggernet server. It will do this as soon as it is powered up and a
PPP connection is established. It will try to open the socket once per
second, until successful. This is done when selecting the “Callback” or
“Konect Router” options in the Mobile Data Assistant program.
Alternatively you can set this by using Campbell Scientific’s device
configuration program to setup the logger and entering the IP address
and socket in the Net Services tab, as a Pakbus/TCP Server setting. This
method is easy to setup and does not rely on code in the data logger
program.
If you are using the Modem IP/Stack the Mobile Data Assistant package
enables a similar function in the modem, which tries to keep open a
permanent connection to the socket to the Konect router or Loggernet.
2)
Alternatively you can call the TCPOpen/TCPClose command in your
program at regular intervals (the speed determines how quickly the
logger will re-establish a broken link). In the TCPOpen command you
need to give the public address of the Loggernet server and the port you
are going to connect on. This method is only normally used where the
logger needs to make more than four connections to different servers,
which is rare. If setting up a modem using the Mobile Data Assistant
Package select the Listen option at the Connection Control stage and
then add code to your program to control outgoing connections.
When using the Modem IP/Stack the modem can be set to only call-back
when it receives data from the attached logger to transmit to Loggernet.
Normally you would trigger the connection by using the standard call-
back commands in the logger program, which would trigger data
exchange with Loggernet on a direct connection, e.g. using
SendGetVariables. To enable this mode you need to use the Advanced
terminal mode of the Mobile Data Assistant program and, after setting
up the modem for call-back, issue the command AT+AUOPT=1,10 to
the modem to tell it to shutdown its PPP connection after 10 minutes of
inactivity.
For either method the port (socket) number must match the call-back port
number either provided when you sign up to the Konect routing service or if
setting the logger to call-back to Loggernet, that entered in the setup screen
of Loggernet (see below) plus you should also enable call-back for the data
logger on the data logger hardware tab.
The method of managing Loggers which call-back over IP varies with the
Loggernet version. Loggernet 4.1 or later is recommended. A description of
how to setup Loggernet for call-back is given in Section 8.2 below.
4.4 Minimising power use
When there is an open PPP/IP connection the average additional power
consumption of the COM111 and data logger, will typically be 30-40 mA.
During communications activity both the data logger and modem power use