Rockwell Automation 1756-DMF30 ControlLogix Drive Module - Manual (Page 23)

1 Publication 1756-UM522B-EN-P - February 2003
Chapter
2
Drive Comm (Drive Communication)
This chapter describes Drive Comm (Drive Communication), the
interface between the ControlLogix Drive module communicates and
Distributed Power System (DPS).
Interface to DPS Drive
Equipment The main function of the Drive module is to interface to Distributed
Power System (DPS) drive equipment, enabling a ControlLogix
processor to control the drive equipment. A ControlLogix processor
performs high level control algorithms and drive coordination. The
Drive module performs outer control loop processing
(1)
, and the
Power Module Interface (PMI) performs real-time control of the
Power Module.
Each drive module interfaces with an individual Power Module
Interface (PMI) processor. It resides in a ControlLogix chassis and
connects to a PMI processor via fiber-optic and Drive Communication
protocol.
Drive Communication
Protocol Drive Communication is a point to point serial link between the Drive
module and the Power Module Interface (PMI), on fiber-optic cable. It
is similar to the protocol used between the Universal Drive Controller
(UDC) and the PMI processor in an AutoMax DPS environment. The
data is Manchester-encoded and transmitted over the fiber-optic links
at a rate of 10M bits per second. Transfers on fiber-optic cables are
immune to electromagnetic interference (EMI).
During initialization, the Drive Module and PMI processor use an
asynchronous master-slave protocol to transfer the PMI operating
system to the PMI processor and to establish synchronized
communication. After initialization, they use synchronized “Set
For information about: See page:
Interface to DPS Drive Equipment 2-1
Drive Communication Protocol 2-1
Initialization 2-2
Synchronized Communication 2-2
Chapter Summary and What’s Next 2-3
(1) The 1756-DMF30 does not perform outer control loop processing - it only functions as a bridge between the
ControlLogix controller and the PMI processor.