Rockwell Automation 20-750-DNET PowerFlex DeviceNet Option Module User Manual
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Rockwell Automation Publication 750COM-UM002B-EN-P - October 2012
Glossary
HIM (Human Interface Module)
A device that can be used to configure and control a drive. The PowerFlex 20-
HIM-A6 or 20-HIM-C6S HIM can be used to configure PowerFlex 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.
Logic Command/Logic Status
The Logic Command is used to control the PowerFlex 750-Series drive (for
example, start, stop, and direction). It consists of one DINT or DWORD of
output from the network to the option module. The definitions of the bits in this
word are shown in
The Logic Status is used to monitor the PowerFlex 750-Series drive (for example,
operating state and motor direction). It consists of one DINT or DWORD of
input from the option module to the network. The definitions of the bits in this
word are shown in
Master-Slave Hierarchy
An option module 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 with installed DeviceNet option
modules) are slave devices.
On a network with multiple scanners (called a multi-master hierarchy), each slave
device must have one scanner specified as a master.
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 non-commissioned devices. Node addresses are
sometimes called ‘MAC IDs’.
NVS (Nonvolatile Storage)
NVS is the permanent memory of a device. Devices such as the option module
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’.