750-841 WAGO, 750-841 Datasheet - Page 144

• Manufacturer Part Number: 750-841
• Description: CONTR.ETHERNET TCP/IP 10/100MBIT
• Manufacturer: WAGO

Specifications of 750-841

• Rohs Compliant: YES
• No. Of Digital Inputs: 10
• No. Of Digital Outputs: 10

136 •
4.1.3.2.1 ETHERNET
4.1.3.3 Channel access method
Fieldbus Communication
ETHERNET
Preamble
8 Byte
Note
If you wish to connect one or more data networks, routers have to be used.
ETHERNET address (MAC-ID)
Each WAGO ETHERNET (programmable) fieldbus coupler or controller is
provided from the factory with a unique and internationally unambiguous
physical ETHERNET address, also referred to as MAC-ID (Media Access
Control Identity). This can be used by the network operating system for
addressing on a hardware level.
The address has a fixed length of 6 Bytes (48 Bit) and contains the address
type, the manufacturer’s ID, and the serial number.
Examples for the MAC-ID of a WAGO ETHERNET fieldbus coupler
(hexadecimal): 00
ETHERNET does not allow addressing of different networks.
If an ETHERNET network is to be connected to other networks, higher-
ranking protocols have to be used.
ETHERNET Packet
The datagrams exchanged on the transmission medium are called
“ETHERNET packets” or just “packets”. Transmission is connectionless; i.e.
the sender does not receive any feedback from the receiver. The data used is
packed in an address information frame. The following figure shows the
structure of such a packet.
Fig. 4-9: ETHERNET-Packet
The preamble serves as a synchronization between the transmitting station and
the receiving station. The ETHERNET header contains the MAC addresses of
the transmitter and the receiver, and a type field.
The type field is used to identify the following protocol by way of
unambiguous coding (e.g., 0800
In the ETHERNET Standard, the fieldbus node accesses the bus using
CSMA/CD (Carrier Sense Multiple Access/ Collision Detection).
•
•
•
Each station can send a message once it has established that the transmission
medium is free. If collisions of data packets occur due to several stations
transmitting simultaneously, CSMA/CD ensures that these are detected and
the data transmission is repeated.
Carrier Sense:
Multiple Access:
Collision Detection: A collision is detected.
14 Byte
ETHERNET-Header
H-
30
H-
DE
The transmitter senses the bus.
Several transmitters can access the bus.
H-
00
H-
hex
00
= Internet Protocol).
H-
01
ETHERNET_Data
46-1500 Byte
H.
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP
Check sum
4 Byte