Nortek DVL 1000 300m, Руководство пользователя

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Appendices 31
© 2017 Nortek AS
9.2 Communication and Ethernet
Connections between the instrument and computer can be made in one of two ways.
Ethernet (via direct connection or router/switch)
RS232/RS422 through the serial port. Serial communication baud rate: 300-115200, 230400,
460800, 625000, 1250000
Details about the Ethernet connection
Most instruments are shipped with the Ethernet option. The first time using the instrument, the
network address needs to be properly configured for the network. The IP address can be assigned in
one of the three ways:
1. Dynamic Host Configuration Protocol (DHCP): A DHCP server in the network is used to assign an
IP address to the Ethernet interface.
2. AutoIP: Link-local address assignment.
3. Manually assign IP address (by the user)
As shipped, the instrument uses options 1 and 2. This means that it will try to automatically
configure the IP address for the network that the instrument is plugged into.
If a DHCP server is detected it takes approximately 30 seconds to negotiate for and assign an IP
address to the Ethernet interface. If you are using a broadband router, it is likely you are using a
DHCP Server to assign IP Addresses. Common private network address schemes include 192.168.
x.x and 10.0.x.x subnets, with the Subnet mask of 255.255.255.0 or 255.255.0.0
If a DHCP server is not detected (usually because of being directly connected to a computer) and the
request for an IP Address is not fulfilled, the instrument will automatically assign itself IP addresses
using the AutoIP protocol. DHCP must first time out before the AutoIP protocol starts, so this will
result in a delay of approximately 90 seconds before an IP address is finally assigned. A standard
AutoIP address sits in the 169.254.x.x range, with the subnet mask being 255.255.0.0.
When using automatic IP address assignment, there is generally no way of knowing which address
was assigned to the instrument. To determine the IP address assigned, the Discovery protocol is
used to query instruments on the local subnet. The discovery protocol is a Nortek proprietary means
for retrieving information from an AD2CP without requiring any knowledge of the IP address
assigned.
There are some limitations on the Discovery protocol. It uses a special type of Ethernet packets
(known as multicast packets) that may not be forwarded through routers (depending upon the router
type and configuration). For that reason, we always recommend that the computer being used for
Discovery ONLY be either directly connected to the instrument or connected through an Ethernet
switch. Only the Discovery protocol uses multicast packets. Other communications use standard
TCP/IP networking which means that the instrument can be communicated with anywhere that IP
connectivity is supported once the IP address is known.
For more details about the DHCP or AutoIP there are many articles available in the public domain.
These are standard protocols used by most Internet based equipment.
Routers
The discovery protocol uses multicast packets that may not work through firewalls and routers. The
Time-to-Live for the multi-cast packets is set to 2. This means that at most one router can sit
between the acquisition system and instruments. The router must also be configured to support
forwarding of multicast packets.
The discovery protocol also supports unicast, so if you know the IP address of the system you can
use the Discover > Search for Address and simply type in the IP address or domain name.