Campbell Scientific PC208 Datalogger Support Software - Manual (Page 75)

5-1
SECTION 5. TELCOM
TELCOM allows IBM-PC compatibles to retrieve and store data from Campbell Scientific dataloggers.
TELCOM includes the protocol to communicate via direct wire, telephone modem, and RF modem. Data
is collected in blocks with error checking to assure data integrity. A station file is created for each
datalogger station which specifies the communications link to the datalogger.
PC208E can be used to create STATION and SCRIPT (schedule) files for TELCOM. TELCOM functions
can be accessed directly from PC208E. See Section 1 (PC208E).
A user can run TELCOM and manually enter the station to call. TELCOM is operated in this attended
manner when a datalogger is brought in from the field and directly interrogated, or the user wants to
observe the telecommunication process as tracked by the screen display. Instead of a single station, a
list of stations or "script" can be input. The user can use a script to manually initiate interrogation or to
start the unattended process.
In unattended operation, TELCOM controls the computer, calling stations on pre-defined intervals, and
trying again later if a call does not go through or is interrupted. DOS commands or other programs can
also be executed on a pre-defined schedule. When the computer is inactive, it can either shut itself off
or stay on and waiting.
TELCOM can also answer incoming calls while in the unattended mode. If the caller is a datalogger, its
data is collected. If the caller is another computer or terminal, execution can branch to a file which sets
up communication with the device.
A number of different files are created and used by TELCOM. The files have a name given by the user
and an extension given by TELCOM. Table 5-1 lists these files.
A station file must be created for each datalogger station to be called. The station file contains all the
information TELCOM needs to make contact with the datalogger and when and how frequently to call.
Once the station file has been created, TELCOM can call the station when the filename is entered. The
data, error, and CQR files are created by TELCOM as needed and given the same name as the station
file.
A station file may also contain a DOS command to be executed. This feature is of use primarily in
unattended operation.
A script file is a list of stations for TELCOM to call. The script file may include station files which are DOS
commands and other script files.
For attended operation, the stations in the script file are listed with an option that forces a call whenever
the station files are executed. The user starts the calling process by running TELCOM and entering the
script file name.