100/180 MM GRAPHICS RECORDER: USER GUIDE
User Guide
Page 31
HA261742
Issue 16 Nov 04
VERTICAL TREND DISPLAY (Cont.)
TIME CHANGE RECORDS
For vertical trend mode only, a line is drawn across the width of the chart whenever a time discontinuity in the record
occurs. These lines are volatile in real-time i.e. they disappear if the display mode is changed, or if a configuration
page is called etc.
Red line
A red line is drawn on the trend history chart at power up.
Blue line
A blue line indicates that recording has been disable/enabled in Group Configuration
, or
by a recording job (
).
Green line
A green line appears if there has been a time change as a result of a clock job (
synchronisation or by the operator physically changing the recorder time.
Note: Changes from standard time to daylight saving time and back again are not 'green lined' in this way
TREND HISTORY
Trend history, allows the user to view the history of the display group. The maximum amount that can be reviewed
depends on a number of factors, including how many points are configured, how rapidly the traces are changing and
so on. At a recording rate of 20 mm/hour (see
group configuration - section 4.3.2
), with all channels configured, a
minimum of 30 day's worth of traces is available for viewing, provided that the group contents are not re-configured
during this period (in which case, the history starts at the end of the re-configuration). The amount of trace visible on
the screen depends on the recording rate, the higher the rate, the less trace is visible at any one time.
Notes:
1.
Trend history mode is not available for groups with 'Recording Enable' disabled (
-
).
2.
Channel cycling is inhibited in trend history mode. To increment the current channel, touch the
faceplate.
3.
Group faceplates are not displayed in trend history mode.
4.
Operation of the Root/Goto View/Message Log key (section 3.2.1), when in history mode, displays a
message log page containing messages which occurred at or near the selected cursor time.
5.
With A/B switching selected, traces are displayed with the 'A' or 'B' span/zone, colour settings etc. ob-
taining at the cursor time. See sections
,
and
, for more details of A/B switching.
To enter trend history mode, the option key can be used (as shown in figure 3.4.1b), or the trace area of the screen can
be continuously touched until the screen blanks prior to re-drawing. A 'Preparing History, please wait' message ap-
pears whilst the re-drawing calculation is taking place. Although tracing stops whilst trace history mode is active, no
data is lost. Process Variable values are saved in the recorder memory. Alarms are still scanned-for and any associated
action taken.
The trend history display is similar to the real-time trend display, with the addition of a slider control and up and
down keys for selecting that part of trend history which is to be displayed. The controls are used as follows:
1
Touching the up/down key causes the trace history to move an incremental amount.
2
Holding the up/down key continuously, causes continuous movement.
3
Touching the bar above or below the slider causes a page-height shift. The Page up and Page down keys can also
be used to provide this function
4
Touching and dragging the slider, whilst observing the time/date display, allows the user to select the section of
history exactly.
On first entry to trend history mode, the channel value and the time and date shown in the faceplate are those at the
top edge of the chart. Touching the screen causes a cursor to appear at point of screen contact. This cursor can be
touched and dragged up and down the screen to provide a reference point on the current trace. The displayed value
date and time refer to the cursor intersection with the current channel. To return to real-time trending, the Option key
is operated, followed by 'Exit History'.
When back in real-time trending, the Horizontal Trend display can be called using the down arrow key. Alternatively,
any one of the enabled display modes (
section 4.3.4
) can be selected using the
Root Menu
, 'Goto View' key.
