Factorytalk historian time expressions – Rockwell Automation FactoryTalk Historian SE ActiveView 3.2 User Guide User Manual

Page 30

Advertising
background image

FactoryTalk Historian ActiveView User Guide

22

Constant

Result

Sunday or sun

00:00:00 (midnight) on the most recent past Sunday (in reference to the

Historian Server).

FactoryTalk Historian Time Expressions

FactoryTalk Historian allows three types of time expressions: relative time,
combined time, and absolute time. These time expression types are defined
in the following table.

Expression

Description

Examples

Relative Time Relative time expressions specify a number of days, hours,

minutes, or seconds with either a leading plus sign or a
leading minus sign.
The reference time, or starting time, for the relative time
expression is the current time if both start and end times are

relative.

+1d
-24h
-3m
+24s

Combined

Time

A combined time expression is a specific reference time

followed by a relative time expression.

*+8h
18-dec-02 -
3m
t+32s

Absolute Time An absolute time expression is any time expression that is

neither a relative nor a combined time expression.

*
14-Dec-97
11-Nov-96
2:00:00.0001
t
y

When using FactoryTalk Historian times, follow these guidelines:

Use absolute or combined time expressions. Avoid using relative time
expressions. Multiple relative time expressions in a time range may
cause an incorrect start time or an error message, depending on the
context of the expression.

Advertising