Siemens SIMATIC S7-300 Series Reference Manual page 64

CPUs
Configuration
Rack max. 4
Modules per module rack max. 8; max. 7 in module
rack 3
Number of DP masters
S
integral None
S
via CP 1
S7 message functions
Simultaneously active max. 40
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
Monitor block Yes
Single sequence Yes
Breakpoint 2
Diagnostic buffer Yes
S
Number of entries 100
(non-alterable)
1-48
Communication functions
PD/OP communication
Global data communication
S
Number of GD packets
– Sender
– Receiver
S
Size of GD packets
– Number of which
consistent
S7 basic communication
S
User data per job
– Number of which
consistent
S7 communication
S
User data per job
– Number of which
consistent
S7-compatible
communication
S
User data per job
– Number of which
consistent
Standard communication
S
User data per job
– Number of which
consistent
Number of connection
resources
S
Reservation for
– PD communication
User-definable
Default
– OP communication
User-definable
Default
– S7 basic
communication
User-definable
Default
Interfaces
1. Interface
Functionality
S
MPI
S
DP Master
S
DP Slave
S
Galvanically isolated
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
Yes
Yes
1
1
max. 22 bytes
8 bytes
Yes
max. 76 bytes
32 bytes for X/I_PUT/_GET;
76 bytes for
X_SEND/_RCV
Yes (server)
max. 160 bytes
32 bytes
Yes (via CP and loadable
FC)
Dependent on CP
Dependent on CP
Yes (via FC and loadable
FC)
Dependent on CP
Dependent on CP
12 for PD/OP/S7 basic/S7
communication
max. 11
from 1 to 11
1
max. 11
from 1 to 11
1
max. 8
from 0 to 8
8
Yes
No
No
No
A5E00111190-01