Siemens SIMATIC S7-1500 System Manual page 381

Isolated modules
In the case of isolated input/output modules, the reference potentials of the control and load
circuits are electrically isolated. Examples are optical isolators, relays or transformers.
Input/output circuits can be connected to common potential.
Load current supply
The load current supply supplies the electric input and output circuits of the module.
MAC address
Each port of a PROFINET interface (PROFINET device) is assigned a unique global device
identifier in the factory. This 6-byte long device identifier is the MAC address.
The MAC address is divided into:
• 3-byte manufacturer ID
• 3-byte device ID (consecutive number)
The MAC addresses are generally shown on the front of the device.
Example: 08-00-06-6B-80-C0
Non-isolated modules
In the case of non-isolated input and output modules, the reference potentials of the control
and load circuits are electrically connected.
NTP
The Network Time Protocol (NTP) is a standard for synchronizing clocks in automation
systems via Industrial Ethernet. NTP uses the UDP connectionless network protocol.
Operating states
Operating states describe the behavior of a single CPU at any given time.
The primary CPU of the S7-1500R/H redundant system has the operating states STOP,
STARTUP, RUN, RUN-Syncup and RUN-Redundant. The backup CPU has the operating states
STOP, SYNCUP and RUN-Redundant.
Organization block
Organization blocks (OBs) form the interface between the operating system of the CPU and
the user program. The organization blocks determine the order in which the user program is
executed.
Pairing
Pairing is the mutual recognition of the CPUs of an S7-1500R/H system within a network.
During pairing, the CPUs exchange information for mutual identification. Example: Checking
for matching article number and firmware version. Successful pairing of two CPUs is a
fundamental requirement for redundant operation.
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
Glossary
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