Saia-Burgess
Controls Ltd.
Manual Modem PCDxx7 Serie│Doc. 26/793; Ed. E2│30.04.2005
Example: Starting an application
5
5-4
Calling
In the example we do it with the timer T19:
On the POWER ON or on the STOP → RUN phase, all the non-retentive flags are re-
setted, so we are sure that, when we call the FB70, the input START_FLAG (M50.0)
is 0. This will start the Driver and initialize the modem. After the first execution of the
FB70 the flag M50.0 is set to 1. As soon the modem and Driver are ready the flag
M50.4 is 1.
A low level (0) on the input START_FLAG done anytime, will reset and initialize again
the Driver and modem.
5.3.
Calling
To give the possibility of calling and getting connected with other subscriber, we
need to integrate the calling function into the project. This is done very easily with the
FC701.
The FC can be called every cycle. It does not affect a possible incoming call and will
not start a call until the required condition are fulfilled.
In this example the calling condition is: the flag M50.4 (DRIVER_READY) is 1 and the
M60.0 also 1. When a rising edge is detected on the CALL_REQ, the calling process
starts.
It will call the phone number 1 in the list (see 5.1.2). If the call can’t be completed the
first time, it will retry it after 3 minutes and 5 attempts in maximum. If it still can’t con-
nect, M60.1 (ERROR) will be set and MW62 will contain the error status.
The function needs internally a TIMER and we allocate the T21, but this TIMER can’t
be used somewhere else in the S7-program anymore.
