Siemens SIMATIC S7-300 Series Reference Manual page 45

Configuration
Rack 1
Modules per module rack max. 8
DP Master
S
integral None
S
via CP Yes
S7 message functions
Simultaneously active None
Alarm-S blocks
Time
Real-time clock Yes
S
Backed-up No
S
Accuracy See Section 1.1.6
Operating hours counter No
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)
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
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 No
communication
Standard communication No
Number of connection 6 for PD/OP/S7 basic/S7
communication
resources
S
Reservation for
– PD communication max. 5
User-definable from 1 to 5
1
Default
– OP communication max. 5
User-definable from 1 to 5
Default 1
– S7 basic max. 2
communication
User-definable from 0 to 2
2
Default
Interfaces
1. Interface
Functionality
S
MPI Yes
S
DP Master No
S
DP Slave No
S
Galvanically isolated No
CPUs
1-29