Siemens SIMATIC S7-300 Series Reference Manual page 88

CPUs
Configuration
Rack max. 4
Modules per module rack max. 8
Number of DP masters
S
integral 2
S
via CP 2
S7 message functions
Simultaneously active
Interrupt S function blocks
and
max. 100
Interrupt D function blocks
Time
Real-time clock Yes
S
Backed-up Yes
S
Accuracy See Section 1.1.6
Operating hours counter 8
S
Number 0 to 7
S
Value range 0 to 32767 hours
S
Selectivity 1 hour
S
Retentive Yes
Clock synchronisation Yes
S
On PLC Master/Slave
S
via MPI Master/Slave
S
via DP Master/Slave
Testing and commissioning functions
Status/Modify Variables Yes
S
Variable Inputs, outputs, flags, DBs,
timers, counters
S
Number max. 70
Force Yes
S
Variable Inputs, outputs, flags,
peripheral inputs, peripheral
outputs
S
Number max. 256
Monitor block Yes
Single sequence Yes
Breakpoint 4
Diagnostic buffer
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 2
S
Size of GD packets 54 bytes
1-72
– 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
Interfaces
1. Interface
Functionality
S
MPI
S
DP Master
S
DP Slave
S
Direct data exchange
S
Default setting
S
Electrically isolated
Number of connections
– Of these, the
following are
reserved:
MPI
S
Services
– PD/OP
communication
– Global data
communication
– S7 basic
communication
– S7 communication
S
Transmission rates
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
32 bytes
Yes
max. 76 bytes
76 bytes
Yes (server)
max. 160 bytes
Byte, Word, Double word
Yes (via CP and loadable
FC)
Dependent on CP
Dependent on CP
Yes (via CP and loadable
FC)
Dependent on CP
Dependent on CP
Yes
Yes
Yes
Yes
MPI
Yes
max. 32;
1 PD connection
1 OP connection
Yes
Yes
Yes
Yes (server)
Up to 12 Mbps
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