Rockwell Automation 1404-M4_M5_M6_M8 Powermonitor 3000 User Manual, Firmware rev. 3.0 or LATER - Manual (Page 80)

80 Publication 1404-UM001F-EN-P - November 2009
Chapter 4 Communication
Data Messaging Overview Through communication, the power monitor becomes an effective
source of power and energy data to enterprise information and
automation systems. This section of the manual provides an overview
of data messaging with the power monitor. Following the overview,
discussions will focus on the details of messaging using specific
communication types (for example, serial, remote I/O, DeviceNet, and
Ethernet).
The power monitor is a read/write data server. It does not initiate data
messages, but responds to messages from client devices. Its data is
organized in data tables similar to those found in a SLC 5/03
programmable controller.
The primary methods to communicate with a power monitor include
the following:
•
Table Writes - A client may write a table of data to the power
monitor. Generally, only full data tables may be written. Data
writes may be performed to configure device features, set the
date and time, reset or preset energy counters, and select
records for subsequent reads.
•
Single Element Writes - Beginning with version 4 master module
firmware, a client may enable single-element writes by writing a
valid password to the Single Element Password Write table.
Single element writes are disabled again after 30 minutes of
inactivity.
•
Simple Data Reads - A client may read metering or configuration
data. The client may read an entire data table or any number of
consecutive data elements up to the table boundary.
•
Indexed Data Reads - The power monitor parses large data
structures such as logs, oscillograms, harmonics and transient
captures into data blocks, records and/or channels. These
records are transferred to an interface table. The client selects
the read-back mode and/or record, reads the interface table and
reassembles the original data structure.
•
I/O Type Communication - The power monitor supports polled,
change-of-state and/or cyclical implicit I/O messaging,
depending on the communication options.
The specific communication setup depends on the communication
port type and protocol, whether serial, Ethernet, or others, as well as
the type of device controlling the communication. The following
sections provide more detail.