Campbell Scientific PC208 Datalogger Support Software - Manual (Page 84)

SECTION 5. TELCOM
5-10
5.4 RUNNING TELCOM UNATTENDED
Unattended operation is possible whether or not
the PC201 Clock and Serial I/O Card and the
PC203 Power up Control Box are installed. The
PC201 and PC203 are necessary if the system
is to power down between calls or to reset itself.
A batch file (name.BAT, see PC-DOS manual)
allows the sequential execution of a number of
programs or commands. If a file named
AUTOEXEC.BAT is on the system disk in the
default drive, it will automatically be run when
the PC is turned on. Incorporating TELCOM in
an AUTOEXEC.BAT file insures that TELCOM
is run when the PC201/PC203 powers up the
PC. Placing TELCOM in an AUTOEXEC.BAT
file also allows a system without the PC203 but
with the PC201 or some other battery-backed
clock to continue the unattended calling process
after a power outage of sufficient duration to
allow the PC to reset.
NOTE: When using the PC201/PC203, the
AUTOEXEC.BAT FILE should contain the
command to set the TELCOM search for
the PC201 card to the port the PC201 is
installed as: e.g. SET PC201 = COM1.
A "Watch Dog" timer is implemented in the
PC201 along with other power control functions.
The timer will run down if there is no evidence
of attended use of the system. The computer is
then powered down and then turned on again,
causing the task to start over again at the start.
The watchdog considers the computer
unattended if the on/off switch of the PC203
power controller is off and the modem is not
active. The modem is considered active only if
the ring signal is detected, followed by a Carrier
Detect signal from the modem.
An "Unattended Active Flag" on the PC201 card
insures that an unattended task is not
permanently interrupted by a temporary AC
power outage. This flag is set when the PC201
wakes the system and is cleared by execution of
the "/D" DONE option. The power control
routines of the PC201 card use this flag along
with other conditions to know when power should
be on. The Unattended Active Flag is
maintained in battery backed RAM so that if an
AC power failure occurs, the state of the flag will
not be lost. When the power returns, the PC201
will know that the Unattended Active Flag is still
set and will switch on power to the PC.
5.4.1 THE DONE (/D) OPTION
The done option (/D, PC201 and PC203
required) is entered as the last line of the script
file (Section 5.3) when it is desired to have the
PC powered down between calls or program
execution.
As TELCOM is executed, it keeps track of the
next time that a station is to be called so it will
know what wake up time to set into the PC201
card. When TELCOM has called all stations, it
sets the wake up time on the PC201 card to
wake up the PC for the next call. When the
wake up time arrives, the PC is powered up by
the PC203, and AUTOEXEC.BAT is executed
again as the system boots. The entire process
is repeated completely unattended.
5.4.2 THE WAIT (/W) OPTION
The wait option (/W) is entered at the last of the
script file when the PC is to remain on between
calls or executing programs. While waiting,
TELCOM will exit to the system if the switch on
the PC203 is turned on or if the escape key
(ESC) or control and C keys (^C) are pressed
on the keyboard.
With no PC203 installed, the wait (/W) option
MUST be used for unattended operation. In this
case, the /W option will only work when the
script file is entered on the command line (e.g.,
'TELCOM STATIONS' where STATIONS.SCR
is described in Section 5.3.2).
5.4.3 ANSWERING INCOMING CALLS -- /A
The /A option is entered as the first line of the
script file if the PC needs to answer incoming
calls while in unattended operation. The /A
must be followed by the COM port that the call
will come in on and the highest expected baud
rate (e.g. '/A com1:1200' or '/A COM3:9600').
When the Hayes Smart modem is the
answering modem switch 6 (Table A-1) must be
up or the ring signal will always be active. If
used with the done option (computer turned off
when not active), the COM port specified must
be the PC201 address.
One of the software functions available for the
21X, CR7X, and CR10(X) is the ability to initiate
telecommunications. With this option, the
datalogger can initiate a call and send a 3 digit
ID number. When TELCOM answers an
incoming call from a datalogger, it looks for a