1. Introduction: Display unit operating concepts
(For more information about how system pages are displayed,
see section "6. System pages", Page 39
.)
The advantage of being able to view these pages with XBT L100• is that system messages can be translated or customized.
Principle of alarm pages
Objective
An alarm page has the same characteristics as an application page with respect to:
- The text
- The field
The advantage of an alarm page lies in its event-triggered display. Each alarm page has an associated dialog-table word bit (
see chapter C, section 4. Dialog table, Page 53
).
If the bit is at state 1, the page is displayed and the text blinks.
A 31/01 17:35 3/7
CONVEYOR FAULT
Switch off.
Remove the part.
B - 18
XBT ref.
N200
Note
No alarm management
Magelis
1. Introduction: Display unit operating concepts
Advantages in run mode
- When a fault appears, it is often the consequence of other faults.
MAGELIS products, due to their priority system, can display the most important fault, i.e., that presenting the highest risk to the controlsystem architecture.
- All faults are time-stamped on appearance.
The actual display of an alarm depends on the priority it has been allocated (
see section "Display priority", Page 19
).
Alarms pending on the control-system architecture are stored in an
"Alarm list".
- The "Alarm" indicator light continuously informs the operator about the state of the alarm list:
- Off: The alarm list is empty.
- Blinking: The alarm list contains alarms, which have appeared since the alarm list was viewed (new alarms).
- On: The alarm list contains alarms, which occurred before the alarm list was viewed (alarms already displayed).
Display priority
A priority can be associated with each alarm page. An alarm page has priority over an application page and a system page. An alarm page does not have priority over a value, which is currently being entered.
Different alarm pages may have different priorities. There are 16 possible levels of priority (the lowest display priority being priority no. 16).
B
XBT ref.
N200
N200/N400/N410
NU400
R400/R410
Magelis
Note
No alarm management
No indicator lights
B - 19
1. Introduction: Display unit operating concepts
Exception for priority 0
If priority 0 is allocated to an alarm page, when the alarm appears on the control-system architecture:
- The alarm page is not displayed, but stored in the alarm list, thus the current display will not be disturbed.
- The alarm indicator light blinks to signal the alarm.
When an alarm is activated, it is stored in the alarm list by the display unit.
Appearance types
There are several types of appearance for an alarm page.
Alarm pages can be:
- Displayed directly on the screen
- Printed directly (data-stream printing)
(1)
- Stored in the list of current alarms
For more information, see chapter C, section Page appearance types,
Page 30
.
Storage principle in the alarm list
If the alarms have equal priority, they are stored from the oldest to the most recent.
If the display unit is available (i.e., not occupied by a higher-priority display), the oldest alarm is displayed. In a control system it is often the oldest alarm, which is the most interesting, as the more recent alarms are often a consequence of the fault signaled by the first alarm (classic case of bursts of alarms).
If higher-priority alarms appear:
- They are stored at the top of the list.
- If the display unit is available (i.e., not occupied by a higher-priority display), the highest priority new alarm is displayed.
XBT ref.
N200
N200/N400/N410
NU400
R400/R410
B - 20
Note
No alarm management
(1) No printer link
Magelis
1. Introduction: Display unit operating concepts
Acknowledgment of alarms
When designing pages, it is possible to define whether the alarm page should be acknowledged systematically by the operator or not
(obligatory acknowledgment).
The alarm page is acknowledged on the display by pressing ENTER.
The alarm message changes to a steady display.
Depending on the choice made, management of these 2 types of alarm is as follows:
B
1 - Alarms, which must be acknowledged (obligatory)
An alarm, which must be acknowledged, remains in the alarm list until it is acknowledged by the operator, even if the cause of the fault has disappeared.
Advantage: Picks up transient faults (instability of a discrete sensor, for example).
2 – Alarms, which can be acknowledged but do not have to be
An alarm, which can be acknowledged but does not have to be, disappears from the alarm list as soon as the cause of the fault has disappeared, regardless of whether or not it has been acknowledged by the operator.
Advantage: The display unit is not monopolized by displays of faults considered of minor importance to the application.
Alarm log
The display units can manage a log of the alarm pages. They store the alarm pages with the text, but without variable values (for more information,
see section Alarm log, Page 41
).
Magelis
XBT ref.
N200
Note
No alarm management
B - 21
1. Introduction: Display unit operating concepts
Display principle of alarm pages
Appearance of an alarm
The ALARM indicator light blinks. The alarm is stored in the alarm list.
Input in progress
No
Yes
End of input or input aborted
Alarm with higher priority already displayed
No
Yes Acknowledgment or disappearance of this alarm
The highest priority alarm that is the oldest alarm not appearing in the list is displayed
XBT ref.
N200
N200/N400/N410
NU400
R400/R410
B - 22
Note
No alarm management
No indicator lights
Magelis
