Rockwell Automation DeviceNet Communications Module - Manual (Page 137)

Glossary Glossary-3
faulted node recovery - DeviceNet feature lets you change a
configuration of a device that is faulted on the network. For
example, if you add a device to a network and it does not have a
unique address, it will fault. If you have a configuration tool that
supports faulted node recovery and your adapter is using
parameters to set its node address and data rate, you can change
the node address.
Flash update - The process of updating firmware in the module.
The module can be flash updated using the X-Modem protocol and
a Serial Converter Module (firmware 3.xx).
heartbeat rate - Used in Change of State (COS) data exchange. It
is associated with producing data once every EPR (Expected
Packet Rate) duration. There may be four heartbeats before a time-
out occurs.
hold last - When communications are disrupted (for example, a
cable is disconnected), the module and MD65 drive can respond by
holding last. Hold last results in the drive receiving the last data
received via the DeviceNet connection before the disruption. If the
drive was running and using the reference from the module, it will
continue to run at the same reference.
I/O Data - Sometimes called “implicit messages” or “input/output,”
transmit time-critical data such as a Logic Command and
Reference. The terms “input” and “output” are defined from the
scanner’s point of view. Output is transmitted by the scanner and
consumed by the module. Input is transmitted by the module and
consumed by the scanner.
Logic Command/Logic Status - The Logic Command is used to
control the MD65 drive (e.g., start, stop, direction). It consists of one
16-bit word of input to the module from the network. The definitions
of the bits in this word depend on the drive.
The Logic Status is used to monitor the drive (for example,
operating state, motor direction). It consists of one 16-bit word of
output from the module to the network. The definitions of the bits in
this word depend on the drive.
MDI - A modification of the ModBus RS-485 serial communication
protocol used by various Reliance Electric drives and power
products to communicate to peripheral devices.
MDI peripheral - A device that provides an interface between MDI
and a network or user. Peripheral devices are also referred to as
“modules” and “adapters.” The DeviceNet module and MD65 OIM
are examples of MDI peripherals.