Siemens SIMATIC S7-300 Module data Hardware And Installation Manual

Configuring
S7-300 Programmable Controller Hardware and Installation
A5E00105492-01
4-45
Example: Terminating resistor in the MPI subnet
The figure below shows you an example of an MPI subnet and where to install the
terminating resistance.
Terminating resistor on
S7-300
Spur line
OP 27
OP 27
PG
PG*
* connect via spur line only during commisioning / maintenance
RS 485-
Repeater
S7-300
SF
BUSF
DC5V
FRCE
RUN
STOP
SIEMENS
SF
BUSF
DC5V
FRCE
RUN
STOP
SIEMENS
S7-300
SF
BUSF
DC5V
FRCE
RUN
STOP
SIEMENS
S7-300
SF
BUSF
DC5V
FRCE
FRCE
RUN
STOP
SIEMENS
Figure 4-19 Activation of the terminating resistors in an MPI subnet
Warning
Disturbance of data traffic might occur on the bus.
A bus segment must always be terminated at both ends with the terminating
resistor. This, for example, is not the case if the last slave with bus connector is off
power.
Since the bus connector draws its power from the station, the terminating resistor
has no effect.
Please make sure that power is always supplied to stations on which the
terminating resistor is active.
As an alternative, you can also use the PROFIBUS Terminator as active bus
termination.

Siemens SIMATIC S7-300 Module data Specifications

General

Series	S7-300
Manufacturer	Siemens
Protection Class	IP20
System	SIMATIC S7-300
Digital Inputs	Varies by module
Digital Outputs	Varies by module
Analog Inputs	Varies by module
Analog Outputs	Varies by module
Central Processing Unit	Varies by CPU model
Supply Voltage	24V DC or 120/230V AC
CPU Type	Varies (e.g., CPU 312, CPU 315, etc.)
Memory	Varies by CPU model
Communication Interfaces	MPI, PROFIBUS
Programming Languages	LAD, FBD, STL, SCL, GRAPH
Operating Temperature	0°C to 60°C
Storage Temperature	-40°C to 70°C
Relative Humidity	10% to 95% (non-condensing)