Technical data

132 • ETHERNET
Network Communication
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP
The DHCP client allows dynamic network configuration of the controller by
setting the following parameters:
Parameter Meaning
IP address of the client Network address of the controller
IP address of the
router
If communication is to take place outside of the local network,
the IP address of the routers (gateway) is indicated in this
parameter.
Subnet mask The Subnet mask makes the controller able to differentiate,
which parts of the IP address determine the network and which
the network station.
IP addresses of the
DNS servers
Here the IP addresses can be entered by maximally 2 DNS
servers.
Lease time Here the maximum duration can be defined, how long the
controller keeps the assigned IP address. The maximum lease
time is 24.8 days. This results from the internal resolution of
timer.
Renewing time The Renewing time indicates, starting from when the controller
must worry about the renewal of the leasing time.
Rebinding time The Rebinding time indicates, after which time the controller
must have gotten its new address.
In the case of configuration of network parameters via the DHCP protocol, the
controller automatically sends a request to a DHCP server after initialisation.
If there is no response, the request is sent again after 4 seconds, a further one
after 8 seconds and again after 16 seconds. If all requests remain unanswered,
a blink code is output via the “IO” LED. Transfer of the parameters from the
EEPROM is not possible.
Where a lease time is used, the values for the renewing and rebinding time
must also be specified. After the renewing time expires, the controller attempts
to automatically renew the lease time for its IP address . If this continually fails
up to the rebinding time, the controller attempts to obtain a new IP address.
The time for the renewing should be about one half of the lease time. The
rebinding time should be about
7
/
8
of the lease time..
5.3.4.6 DNS (Domain Name Systems)
The DNS client enables conversion of logical Internet names such as
www.wago.com into the appropriate decimal IP address represented with
separator stops, via a DNS server. Reverse conversion is also possible.
The addresses of the DNS server are configured via DHCP or web-based
management. Up to 2 DNS servers can be specified. The host identification
can be achieved with two functions, an internal host table is not supported.