Siemens SIMATIC S7-300 Series Reference Manual page 83

Address areas (I/O)
Peripheral address area, 2 KB/2 KB (freely
digital/analog addressable)
S
Distributed 2 KB/2 KB
Process image (cannot be 128/128 bytes
customized)
Digital channels max. 16384 (minus 1 byte
diagnostic address per DP
slave)/16384
S
Centralized max. 1024/1024
Analog channels max. 1024 (minus 1 byte
diagnostic address per DP
slave)/1024
S
Centralized max. 256/128
Configuration
Rack max. 4
Modules per max. 8
Rack
Number of DP masters
S
integral 1
S
via CP 1
S7 message functions
Simultaneously active max. 50
Alarm-S blocks
Time
Real-time clock Yes
S
Backed-up Yes
S
Accuracy See Section 1.1.6
Operating hours counter 1
S
Number 0
S
Value range 0 to 32767 hours
S
Selectivity 1 hour
S
Retentive Yes
Clock synchronisation Yes
S
On PLC Master
S
On MPI Master/Slave
Testing and commissioning functions
Status/Modify Variables Yes
S
Variable Inputs, outputs, flags, DBs,
timers, counters
S
Number
– Monitor Variables max. 30
max. 14
– Modify Variables
Force Yes
S
Variable Inputs, outputs
S
Number max. 10
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
Monitor block Yes
Single sequence Yes
Breakpoint 2
Diagnostic buffer Yes
S
Number of entries 100
(non-alterable)
Communication functions
PD/OP communication Yes
Global data communication Yes
S
Number of GD packets
– Sender 1
– Receiver 1
S
Size of GD packets max. 22 bytes
– Number of which 8 bytes
consistent
S7 basic communication Yes
S
User data per job max. 76 bytes
– Number of which 32 bytes for X/I_PUT/_GET;
consistent
76 bytes for
X_SEND/_RCV
S7 communication Yes (server)
S
User data per job max. 160 bytes
– Number of which 32 bytes
consistent
S7-compatible Yes (via CP and loadable
communication FC)
S
User data per job Dependent on CP
– Number of which Dependent on CP
consistent
Standard communication Yes (via CP and loadable
FC)
S
User data per job Dependent on CP
– Number of which Dependent on CP
consistent
Number of connection 12 for PD/OP/S7 basic/S7
resources communication
S
Reservation for
– PD communication max. 11
User-definable from 1 to 11
1
Default
– OP communication max. 11
User-definable from 1 to 11
1
Default
– S7 basic max. 8
communication
from 0 to 8
User-definable
8
Default
Routing connections max. 4
CPUs
1-67