4
Data Exchange between User Program and AS−i Slaves
47
CP 343−2 / CP 343−2 P AS−Interface Master
Release 08/2008
C79000−G8976−C149−04
4.3
Points to Note about Binary Data of Analog Slaves
4.3.1
Point to Note About Analog Slaves
If you use slaves complying with CTT 1−5, all or some I/O bits may be used for
special transfer functions.
The following applies to these protocol bits:
S
In the input direction, the CP sets the value “0”.
S
In the output direction, the CP ignores the bits;
How to access AS-i analog slaves is described in Section 4.4.
4.3.2
Points to Note About AS-i Safety Slaves
The CP sets the input bits
S
0 and 1 = 0 if the contact at F−IN1 is open;
S
0 and 1 = 1 if the contact at F−IN1 is closed;
S
2 and 3 = 0 if the contact at F−IN2 is open;
S
2 and 3 = 1 if the contact at F−IN2 is closed;
4.4
Transferring AS-i Analog Values
Notice
The following descriptions apply only to AS−i slaves whose data is stored in the
analog area. Analog value transfer in compliance with AS-i slave profile 7.1/7.2 is
not supported by the CP 343-2. In this case, analog value transfer must be imple-
mented in your software.
Analog Interface between the PLC CPU and CP 343-2
You can operate up to 31 AS-i slaves each with up to 4 analog input or 4 analog
output values.
You can operate up to 62 analog slaves in the A/B area each with up to 2 analog
input or analog output values.
You access the analog values of AS-i analog slaves in the user program using the
system function blocks SFC 58 / SFC 59 (“write_data_record” /
“read_data_record”). For this function, you use data record numbers 140−147.
