Technical specifications
8.5 Hardware description
SIMATIC IPC277E
Operating Instructions, 11/2019, A5E35783335-AE
123
Watchdog enable register / 066h select register (r/w address 062h)
Trigger red Watchdog LED
0
Red LED (WD) off
1
Red LED (WD) on
Watchdog error / Display and reset
0
WD inactive
1
WD triggered
Reset LED after watchdog alarm
(Bit 7 = write 1)
8.5.4.3
Watchdog trigger register (read only, address 066h)
Watchdog trigger register
The watchdog is triggered by a read action (address 066h) by this register. The result of the
read access can be disregarded (i.e., dummy read).
8.5.4.4
Battery status register (read-only, address 50Ch)
The status of the CMOS battery is monitored; the status (two-tier) can be read from the
battery status register.
Meaning of the bits
Battery status register (read-only, address 404Dh)
Bit
Meaning
7 6 5 4 3 2 1 0
0 0
CMOS battery capacity is still sufficient.
0 1
CMOS battery capacity is exhausted (remaining capacity is
sufficient for approx. one month)
1 1
CMOS battery is empty
