Siemens C79000-Z7076-C552-01 ユーザーズマニュアル

New Functions in Version V4.02

17

Supplement to the STEP 7 User Manual V4.0
C79000-Z7076-C552-01

The following table provides an overview of the functions and summarizes the
differences between forcing and modifying.

Bit memory (M)

yes

Timers and counters (T, C)

no

no

yes

Data blocks (DB)

no

no

yes

Peripheral inputs (PIB, PIW, PID)

no

Peripheral outputs (PQB, PQW, PQD)

yes

yes *

yes

Inputs and outputs (I, Q)

yes

yes *

yes

Defining triggers

always trigger
immediately

always trigger
immediately

yes

(once or every
cycle)

Function only affects variable in visible
area of active window.

affects all
force values

affects all
force values

yes

User program can overwrite the modify/
force values.

yes  *

yes

Replacing the force value effective without
interruption.

yes

yes

no

The variables retain their values when
application is exited.

yes

yes

no

Variables retain their values after the
connection to the CPU is broken.

yes

yes

no

Variables retain their values after power
off, provided CPU has battery backup.

yes

yes

no

Address error permitted:

e.g.: 

IW1 modify/force value: 1

IW1 modify/force value: 0

no

no

yes

the last
becomes
effective

* The inputs (process-image input table) occupied by force values can be overwritten with:
- write instructions (for example, T IB x;  = I x.y; copying with SFCs)
- read instructions (for example, L PIW x)
- write programming device/operator panel functions
The outputs occupied by force values can be overwritten with:
- write instructions (for example, T PQB x)
- write programming device/operator panel functions