Reading data from the trend log – Rockwell Automation 1404-M4_M5_M6_M8 Powermonitor 3000 User Manual, Firmware rev. 3.0 or LATER User Manual

Page 152

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Publication 1404-UM001F-EN-P - November 2009

Chapter 7 Data Logging

The power monitor clears the trend log when you change any
parameter or the logging interval.

You may perform a simple table read of the

Trend Log

Configuration/Read-back Record Select

table to view the existing

Trend Log configuration.

When you read this table, the password element returns a value of -1
and the reserved and command elements return a value of 0. Elements
7 and 8 return the Total Records Logged * 1000 and * 1 respectively.

Reading Data from the Trend Log

To read the Trend Log, use the indexed read method.

A write to the

Trend Log Configuration/Read-back Record Select

table

selects which trend log record is read next.

There are a number of auto-increment and manual-increment options
that may be selected by writing to the Read-back Mode element in the

Trend Log Configuration/Read-back Record Select Parameters

table.

You can select from the following options:

0 - Auto-increment / start at beginning: Start at the oldest log
record and index to the next record after each read of the results
table

1 - Auto-increment / start at end: Start at the newest log record
and index to the next record after each read

2 - Auto-decrement / start at end: Start at the newest log record
and index to the previous record after each read

3 - Point to the oldest log record

4 - Point to the newest log record

5 - Index to the next record after each read of the results table

6 - Index to the previous record after each read

TIP

Although you may configure up to 16 Trend Log parameters on units
with optional DeviceNet communication, the results table will return
only the first 8.

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