Rockwell Automation 20-750-PNET Profinet Single Port Option Module - Manual (Page 87)

Rockwell Automation Publication 750COM-UM006A-EN-P - January 2013 87
Glossary
HIM (Human Interface Module) A device that can be used to configure and control a drive. The Power Flex 20-
HIM-A6 or 20-HIM-C6S HIM can be used to configure Power Flex 750-Series
drives and their connected peripherals.
Hold Last When communication is disrupted (for example, a cable is disconnected), the
option module and PowerFlex drive can respond by holding last. Hold last results
in the drive receiving the last data received via the network connection before the
disruption. If the drive was running and using the Reference from the option
module, it will continue to run at the same Reference.
Idle Action An idle action determines how the option module and connected drive act when
the controller is switched out of run mode.
I/O Data I/O data, sometimes called ‘implicit messages’ or ‘input/output’, is time-critical
data such as a Logic Command and Reference. The terms ‘input’ (To Net) and
‘output’ (From Net) are defined from the controller's point of view. Output is
produced by the controller and consumed by the option module. Input is
produced by the option module and consumed by the controller.
IP Address A unique IP address identifies each node on the Profinet network. An IP address
consists of 32 bits that are divided into four segments of one byte each. It appears
as four decimal integers separated by periods (xxx.xxx.xxx.xxx). Each ‘xxx’ can
have a decimal value from 0 to 255. For example, an IP address could be
192.168.0.1.
An IP address has two parts: a network ID and a host ID. The class of network
determines the format of the address.
The number of devices on your Profinet network will vary depending on the
number of bytes that are used for the network address. In many cases you are
given a network with a Class C address, in which the first three bytes contain the
network address (subnet mask = 255.255.255.0). This leaves 8 bits or 256
addresses on your network. Because two addresses are reserved for special uses (0
is an address for the network usually used by the router, and 255 is an address for
broadcast messages to all network devices), you have 254 addresses to use on a
Class C address block.
0 1 7 15 23 31
Class A 0 Network ID Host ID
0 1 7 15 23 31
Class B 1 0 Network ID Host ID
0 1 2 7 15 23 31
Class C 1 1 0 Network ID Host ID