Ac500-S - ABB AC500 V3 System Manual

I/O modules
If the number of onboard I/Os provided on the processor module is insufficient for a certain use
case, the PLC can be expanded with I/O modules to meet the control requirements.
Memory In the PLC, the memory is mainly used for saving system programs, user programs and work
data. There are two types of memory:
● Volatile memory:
All saved data will be lost after power failure of the memory but the memory can provide
a high access rate and unlimited programming cycles. Common volatile memories mainly
include SRAM and DRAM (including common memories such as SDRAM).
● Nonvolatile memory:
All saved data will not be lost after power failure of the memory, but the memory is subject
to a low read-write rate and limited rewrite cycles. Common nonvolatile memories mainly
include NORflash, NANDflash, EEPROM, memory card, etc.
AC500 PLCs store all user programs in the nonvolatile memory to protect them from power
failure. The programs are exported to the volatile memory during PLC operation to ensure
high-speed and efficient operation. If user program debugging is finished, the programs can
be fixed in the nonvolatile memory when they need no change. The work data is subject to
frequent change and access during PLC operation. It is saved in the volatile memory to meet
the requirements for random access.
The work data memory of the PLC has the memory area for input and output relay, auxiliary
relay, timer, counter and other logic devices. The state of these devices depends on initial
setting and operation of the user programs. Some data maintains its existing state by using
built-in supercapacitors or backup batteries in the event of a power failure. The memory area for
data saving in the event of a power failure is called the data retention area.
Power supply The PLC is equipped with a switching power supply for the internal supply. In comparison with
an ordinary power supply, the switching power supply has a higher stability and a higher noise
immunity.
Some modules include a stabilized power supply for the supply of external sensors.

3.6 AC500-S

Functional The AC500-S safety user manual must be read and understood before using the safety configu-
safety ration and programming tools of Automation Builder/PS501 Control Builder Plus. Only qualified
personnel are permitted to work with AC500-S safety PLCs.
The AC500-S safety PLC includes the following safety-relevant hardware components.
● SM560-S/SM560-S-FD-1/SM560-S-FD-4
● DI581-S
2023/03/03 3ADR011074, 1, en_US
System overview
AC500-S
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