Rockwell Automation 20A PowerFlex 70EC/700VC - Manual (Page 41)

DPI 37
DPI Drive Peripheral Interface (DPI) is a CAN based, Master-Slave protocol, created to
provide a standard way of connecting motor control products and optional
peripheral devices together. It allows multiple (up to 6) devices to communicate
with a motor control product without requiring configuration of the peripheral. DPI
provides two basic message types called Client/Server (C/S) and Producer/
Consumer (P/C). Client/Server messages are used to transfer parameter and
configuration information in the background (relative to other message types).
Producer/Consumer messages are used for control and status information. Multiple
devices can be attached to and communicate with drives at the same time. This
communication interface is the primary way to interact with, and control the drive.
Important: The PowerFlex 700 Vector Control option only supports the DPI
communication protocol. It will not communicate with SCANport
peripheral devices (previous generation HIM and communication
adapters).
Client/Server Operation
Client/Server messages operate in the background (relative to other message types)
and are used for non-control purposes. The Client/Server messages are based on a
10ms “ping” event that allows peripherals to perform a single transaction (e.g. one
C/S transaction per peripheral per time period). Message fragmentation (because
the message transaction is larger than the standard CAN message of eight data
bytes) is automatically handled by Client/Server operation. The following types of
messaging are covered:
•
Logging in peripheral devices
•
Read/Write of parameter values
•
Access to all parameter information (limits, scaling, default, etc.)
•
User set access
•
Fault/Alarm queue access
•
Event notification (fault, alarm, etc.)
•
Access to all drive classes/objects (e.g. Device, Peripheral, Parameter, etc.)
Producer/Consumer Operation
Producer/Consumer messages operate at a higher priority than Client/Server
messages and are used to control/report the operation of the drive (e.g. start, stop,
etc.). A P/C status message is transmitted every 5ms (by the drive) and a command
message is received from every change of state in any attached DPI peripheral.
Change of state is a button being pressed or error detected by a DPI peripheral.
SCANport devices are slightly different in that those peripherals transmit command
messages upon reception of a drive status message rather than on detection of a
change of state. Producer/Consumer messages are of fixed size, so support of
message fragmentation is not required. The following types of messaging are
covered:
•
Drive status (running, faulted, etc.)
•
Drive commands (start, stop, logic parsing, etc.)
•
Entering Flash programming mode
•
“Soft” login and logout of peripheral devices (enabling/disabling of peripheral
control)
70EC 700VC 700H
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