Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 09/2008, A5E02191071-01
161
6.5.2
Interface status of the CP 341, checking
The FC V24_STAT reads the RS 232C accompanying signals from the CP 341 and makes
them available to the user in the block parameters. The FC V24_STAT is called cyclically or,
alternatively, statically (without conditions) in a time-controlled program.
The RS 232C accompanying signals are updated each time the function is called (cyclic
polling). The CP 341 updates the status of the inputs/outputs in a time grid of 20 ms. The
inputs/outputs are constantly updated independently of this.
The binary result BR is not affected. The function does not issue error messages.
The LADDR parameter defines the CP 341 to be addressed.
What is to be done?
Block call
STL representation
LAD representation
CALL
V24_STAT
LADDR:
=
DTR_OUT:
=
DSR_IN:
=
RTS_OUT:
=
CTS_IN:
=
DCD_IN:
=
RI_IN:
=
9B67$7
(1
/$''5
'75B287
(12
'65B,1
576B287
&76B,1
'&'B,1
5,B,1
Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR.
Assignment in the data area
The FC V24_STAT function does not occupy any data areas.
Note
A minimum pulse duration is necessary to detect a signal change. Determining factors are
the CPU cycle time, the update time on the CP 341, and the response time of the
communication partner.
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