Direct Connection (Isolated Network); Address Restrictions - Keithley 2701 Instruction Manual

3-4 Configuring TCP/IP addresses

Direct connection (isolated network)

When connecting the device directly to the Ethernet port of a PC or to a hub that is not part
of a larger network, the IP address and Subnet mask must be configured manually (the gateway
address is not relevant in this case).
The IP address is a 32-bit identifier consisting of four one byte (8-bits) sections, commonly
notated in dotted decimal format (i.e. 145.90.120.240). The Subnet mask is a second 32-bit
identifier that designates what portion of the IP address identifies the subnet and what portion
identifies the device (i.e. 255.255.255.0). In this example, 145.90.120 is the network address
and 240 is the device address. Gateway addresses are typically the device address 1 (e.g.,
145.90.120.1).
Networks are commonly grouped into three classes based on the first byte of the address:
Table 3-2
Network classes
Class
A
B
C

Address restrictions

NOTE
The following IP addresses are reserved—do not assign them to any device (either interface
card or Model 2701):
Do not assign...
any address beginning (first byte) with 0 or 127 (reserved for loopback test),
any address beginning (first byte) with 224 through 255,
any address ending (last byte) with 0 or 255.
Other than the restricted addresses, any dis-similar address may be assigned to the PC's
Ethernet interface card and to each Model 2701. Keep in mind that when creating and assign-
ing an address, the one assigned to the Model 2701 has to be of the same class as the network.
For example, if you want the Model 2701's IP address to be 192.168.0.2 (the default), the Sub-
net mask should be 255.255.255.0. Also, to communicate with the Model 2701, the PC's Ether-
net Interface card must be set to the same class (same Subnet mask and Network ID).
NOTE
First Byte Typical Subnet Mask
1 to 127 255.0.0.0
128 to 191 255.255.0.0
191 to 223 255.255.255.0
Different available IP addresses are required for each node (this includes each 2701
and each network interface card connected to the instruments network).
Without the correct Subnet mask or Network ID, the direct network will not function.
Model 2701 Instrument Networking Instruction Manual
IP Address Example
100.1.1.1
128.1.1.1
191.1.1.1