User manual

CS-GSM/GPRS Digital Transceiver Kits (including the COM110A modem)

To add this setting, use the Phone modem option in Loggernet where you can edit

the modem initialisation string in the setup screen. You cannot amend this setting

for a TAPI interface in a way that Loggernet can also detect.

Campbell Scientific communications software includes other time-outs which are

used to check for hung communications links. These are set to be quite short for

land-based modems, as the response to any command sent from the PC should be

almost instantaneous. A link to a remote COM110A modem normally passes

through several nodes of a digital data network, all of which can add delays.

Usually these delays are less than one second and so have no effect on the

communications process. However, on a long distance call or busy network, the

built in time-out delay for the PC software may need to be extended.

In Loggernet or PC400W, a station-specific delay can be added by increasing the

time in the ‘Extra response time’ box shown on the datalogger hardware set-up

screen. This delay is entered in seconds. Loggernet has a default, built-in, delay of

~2 seconds, which is adequate for use with the COM110A modem in most cases.

On busy networks, or with poor communication links, a value of 3 or even 4 may

be required, to allow the error correction process to function.

Where a COM110A modem is used as the base station modem, it is advisable to

increase these delays even more by perhaps another 1-2 seconds, if

communications are proving to be unreliable.

Entering too large a delay can slow down the entire communications

process, and so an optimal value should be determined by trial and

error.

9. Using Loggernet for GPRS communications

9.1 Setting up to call a logger with a fixed IP address

Where there are no restrictions on outgoing connections from Loggernet to the

remote IP address, the connection can be setup as a standard IPPort connection as

documented in the help system. An example is shown below. The only change

from entering the IP address and port in the normal way is the an “Extra response”

delay of a few seconds may be required when using a slow connection.

Do not extend the extra response beyond 5 secs as it is not

beneficial.

NOTE