Rockwell Automation 20-COMM-M Modbus/TCP Adapter User Manual
Page 91
Glossary
G-5
20-COMM-M Modbus/TCP Adapter User Manual
Publication 20COMM-UM014C-EN-P
L
Logic Command/Logic Status
The Logic Command is used to control the PowerFlex 7-Class drive (for
example, start, stop, direction). It consists of one 16-bit word of output to
the adapter from the network. The definitions of the bits in this word depend
on the drive, and are shown in
.
The Logic Status is used to monitor the PowerFlex 7-Class drive (for
example, operating state, motor direction). It consists of one 16-bit word of
input from the adapter to the network. The definitions of the bits in this
word depend on the drive, and are shown in
.
M
Modbus/TCP Network
Modbus/TCP is an open network designed for use in industrial
environments. Modbus/TCP allows industrial devices to perform control,
configuration, and monitoring tasks using standard Ethernet IEEE 802.3
equipment, the TCP/IP protocol (which uses Ethernet II framing), and the
Modbus/TCP protocol. Modbus/TCP by itself, as with any Ethernet-based
protocol, does not address control determinism issues, though they can be
minimized by network design and the use of commercial network switches.
N
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.”
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 DriveExecutive) also use PCCC to communicate.
Ping
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. On Ethernet, a ping can
be used to determine if a node exists.
PowerFlex 7-Class (Architecture Class) Drives
The Allen-Bradley PowerFlex 7-Class family of drives supports DPI and
includes the PowerFlex 70, PowerFlex 700, PowerFlex 700H, PowerFlex
700S, PowerFlex 700L, and PowerFlex 7000. These drives can be used for
applications ranging from 0.37…3000 kW (0.5…4000 HP).