|
TCS 3.5 on-line instructions
|
|
|
|
Modem sharing feature
In some applications, like in industrial automation, a machine controller, i.e. a PLC
has already a RS232 port to communicate with a modem., so it could already be
remotely controlled simply using a GSM modem, without the need of a much more
sophisticated TCS board.
Nevertheless most of the times these installations lack of local intelligence
to receive and send data via SMS or perform additional controls, features available
on a TCS board.
At this point we receive a typical question: Can I use the modem installed in the
TCS board to communicate with my PLC?
With the TCS 3.0 the answer was NO.
With the TCS 3.5 the answer is YES, but...
The thing to consider is that you have 1 modem and you can't connect 2 things at
the same time. If you decide to switch the modem to your external device you must
be aware that it won't be possible to control the TCS because it has no access to
the modem hence it can't send alarms or receive commands.
To try to cope with this problems we have implemented the DDC command.
With the DDC ( Switch Direct Data Call) command you can choose where the next
incoming data call will be routed. A command #DDC0 routes them to the external
RS232 port, a command #DDC1 routes them to the TCS Operating System.
To allow a PC or an external device to have direct access to the modem of the
TCS and use it autonomously we have implemented the #CTR command. Once issued,
this command connects the RS232 port directly to the modem for an amount of seconds
that has to be specified with the command. Once the amount of time is over, TCS will
regain control of the modem.
Important: To be able to use this features properly you must be quite skilled because
you must be able to control the modem properly and issue the commands in a way
that doen's prevent proper operation of the system. We don't provide low level
assistance about doing it. These features are domain of experienced users.
|
