Technical data

Appendix
27.1 Operating Modes
Programming with STEP 7
570 Manual, 05/2010, A5E02789666-01
27.1.5 HOLD Mode
The HOLD mode is a special mode. This is only used for test purposes during startup or in RUN
mode. The HOLD mode means the following:
• All timers are frozen: timers and runtime meters are not processed, monitoring times are
stopped, the basic clock pulses of the time-driven levels are stopped.
• The real-time clock runs.
• Outputs are not enabled but can be enabled explicitly for test purposes.
• Inputs and outputs can be set and reset.
• If a power outage occurs on a CPU with a backup battery while in HOLD mode, the CPU
changes to stop when the power returns but does not execute an automatic hot restart or
restart (warm restart). CPUs without battery backup execute an automatic restart (warm
restart) when power returns.
• Global data can be received and passive one-way communication using communication SFBs
for configured connections and communication SFCs for non-configured connections is
possible (see also table in RUN Mode).