DPI 2-83
DPI Drive Peripheral Interface (DPI) is an enhancement to SCANport that
provides more functions and better performance. SCANport was 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. SCANport and
DPI both provide 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. DPI adds a higher baud rate, brand specific
enabling, Peer-to-Peer (P/P) communication, and Flash Memory
programming support. PowerFlex 70 & 700 support the existing SCANport
and DPI communication protocols. Multiple devices of each type
(SCANport or DPI) can be attached to and communicate with PowerFlex 70
& 700 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.
Client/Server
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 (i.e. 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 overview
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
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