Allen-Bradley PowerFlex 20-COMM-D, Руководство пользователя

Страница: 138 / 149

Glossary-6
M
Master-Slave Hierarchy
An adapter configured for a master-slave hierarchy exchanges data with
the master device. Usually, a network has one scanner which is the
master device, and all other devices (for example, drives connected to
DeviceNet adapters) are slave devices.
On a network with multiple scanners (called a multimaster hierarchy),
each slave device must have a scanner specified as its master.
N
Node Address
A DeviceNet network can have as many as 64 devices connected to it.
Each device on the network must have a unique node address between 0
and 63. Node address 63 is the default used by uncommissioned devices.
Node addresses are sometimes called “MAC IDs.”
NVS (Non-Volatile Storage)
NVS is the permanent memory of a device. Devices such as the adapter
and drive store parameters and other information in NVS so that they are
not lost when the device loses power. NVS is sometimes called
“EEPROM.”
O
Objects
The DeviceNet specification defines an object as “an abstract
representation of a particular component within a product.”
P
PCCC (Programmable Controller Communications Command)
PCCC is the protocol used by some controllers to communicate with
devices on a network. Some software products (for example,
DriveExplorer and DriveTools 2000) also use PCCC to communicate.
Peer-to-Peer Hierarchy
An adapter that is configured for a peer-to-peer hierarchy can exchange
data with a device on the network that is not a scanner. This type of
hierarchy can be set up so that a scanner configures or transmits data to
one PowerFlex drive which then sends the same configuration or data to
other PowerFlex drives on the network. To use a peer-to-peer hierarchy,
you configure one adapter to transmit data (2 – 4 words) and one or more
adapters to receive the data.
Ping
A ping is a message that is sent by a DPI product to its peripheral
devices. They use the ping to gather data about the product, including
whether it can receive messages and whether they can log in for control.