Siemens SIMATIC S7-300 Module data Hardware And Installation Manual

Testing functions, Diagnostics and Fault Elimination
S7-300 Programmable Controller Hardware and Installation
A5E00105492-01
10-3
PIQ
transfer
Execute force
job for inputs
Execute force
job for inputs
T PQW
OS
PII
transfer
User program
Forced value
Forced value
overwritten by T
PQW!
With S7-300-CPUs, forcing is the same as “cyclical modify“
OS: operating system execution
PIQ
transfer
OS
PII
transfer
Forced value
Execute force
job for outputs
Execute force
job for outputs
Figure 10-1 Principle of Forcing with S7-300 CPUs (all CPUs except 318-2 DP)
Differences between Forcing and Controlling of Variables
Table 10-1 Differences between Forcing and Controlling of Variables
Characteristics/Function Forcing with
CPU 318-2 DP
and S7-400
Forcing with
S7-300
without 318-2 DP
Controlling
Variables
Memory bit (M) Yes - Yes
Timers and counters (T, C) - - Yes
Data Blocks (DB) - - Yes
Inputs and outputs (I, Q) Yes Yes Yes
Peripheral Inputs (PI) Yes - -
Peripheral Outputs (PO) Yes - Yes
User program can overwrite
control/force values
-YesYes
Maximum number of force
values
256 10 -
Cross-reference
Details on test functions of the software are found in the STEP 7 Online Help and
in the STEP 7 Programming Manual.

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)