Clocks On The C7 - Siemens simatic c7-621 Hardware Installation Manual

Installing and Preparing the C7

2.12 Clocks on the C7

Overview
The C7 devices have two software clocks:
Clock on the The clock of the C7 CPU is a software clock. This clock is independent of
C7 CPU the clock of the C7 OP.
Default
When the unit is shipped, the following value is set:
C7 CPU Time
DT#1994-0-01-00:00:00.
Master Clock As an integrated clock, the C7 CPU clock can also function as the master
clock within the C7 I/O configuration.
Setting and You set and read the time as follows:
Reading Out the
C7 CPU Clock
Clock Reaction to
If the power is turned off, the current time is saved in the non-volatile
Power Off
memory. When power is turned on again, the clock continues to run starting
from the saved time.
When the power is turned off, the C7 CPU clock itself stops.
Clock on the
The clock on the C7 OP is independent of the clock on the C7 CPU. When
C7 OP the power is turned off, the C7 OP clock stops.
Default OP Time When the device is shipped, the clock is set to the following value:
01.01.94 -00:00.
Setting and
You set the time as follows:
Reading Out the
C7 OP Clock
2-24
One clock on the C7 CPU
One clock in the C7 OP
With a programming device using STEP 7
or
In the STEP 7 user program using SFC 0 "SET_CLK". With SFC 1
"READ_CLK" you can read out the current time (refer to the reference
manual /235/).
Using a job in the user program and interface block.
or
Online by selecting the special display "Time/Date" if this was
configured.
C7-621 / C7-621 AS-i Control Systems
C79000-G7076-C621-01