
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
-
Yes
Yes
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.
Содержание Simatic S7-300
Страница 10: ...Contents S7 300 Programmable Controller Hardware and Installation x A5E00105492 01 ...
Страница 16: ...Preface S7 300 Programmable Controller Hardware and Installation 1 6 A5E00105492 01 ...
Страница 22: ...Quick Guide S7 300 Programmable Controller Hardware and Installation 2 6 A5E00105492 01 ...
Страница 28: ...Product overview S7 300 Programmable Controller Hardware and Installation 3 6 A5E00105492 01 ...
Страница 74: ...Configuring S7 300 Programmable Controller Hardware and Installation 4 46 A5E00105492 01 ...
Страница 102: ...Wiring S7 300 Programmable Controller Hardware and Installation 6 18 A5E00105492 01 ...
Страница 148: ...Commissioning S7 300 Programmable Controller Hardware and Installation 8 36 A5E00105492 01 ...
Страница 236: ...Glossary S7 300 Programmable Controller Hardware and Installation 12 16 A5E00105492 01 ...