Dräger Polytron 8100, Инструкция по эксплуатации, Страница: 21 / 254

Menu
Dräger Polytron 8100 21
5.8 Settings instrument
5.8.1 Alarm settings
With factory default settings and during normal operation, the
relays are energized. This provides a “fail-safe” operation.
To switch the alarm On or Off:
1. Select Settings > Instrument > Alarm > Alarm on/off .
2. Select Enable or Disable and confirm.
Using relays the maintenance signal is transmitted via the 4-
20mA interface and the symbol [
] is displayed when the
alarm is set to off.
Configuring Relay A1 or A2
This function defines whether the alarm relay is energized
during normal operation or energized at an alarm condition.
If the configuration of the relay is set to “Normally energized”,
the relay contact is asserted during normal operation and
changes if an alarm is triggered. At a loss of power this will
trigger an alarm (fail-safe). The fault relay is factory-configured
to “Normally energized” and cannot be changed.
To configure relay A1 or A2:
1. Select Settings > Instrument > Alarm > Relay A1 or
Relay A2 and confirm.
2. Select Normally energ. or Energ. on alarm and confirm.
Configuring Alarm A1 or A2
To configure alarm A1 or A2:
1. Select Settings > Instrument > Alarm > Alarm A1 or
Alarm A2 and confirm.
The current alarm set-point is displayed.
2. Set the alarm set-point and confirm.
3. Select
Next and confirm.
The current alarm direction is displayed.
4. Select Rising or Falling and confirm.
5. Select Next and confirm.
The current alarm latch mode is displayed.
6. Select Latching or Non Latching and confirm.
7. Select Next and confirm.
The current acknowledgement mode is displayed.
8. Select Acknowledgeable or NonAcknowledgeabl or
PreAcknowledgeabl and confirm.
9. Select Next and confirm.
The current hysteresis is displayed.
10. Set the hysteresis and confirm.
11. Select
Next and confirm.
A confirmation screen shows all settings.
12. Select Confirm and confirm with [OK].
The new settings are now saved.
Repeat settings for A1 or A2 respectively.
Case: Alarm is acknowledged before and after the alarm condition cleared.
Latching
Non-acknowledgeable 1 Alarm condition is present.

Relay (b) is energized and symbol (b) is active.

LED (c) starts flashing.
2 Alarm is about to be acknowledged (d), but acknowledging is not
possible.

Relay (b) stays energized and symbol (b) stays active.

LED (c) keeps flashing.
3 Alarm condition clears.

Relay (b) stays energized and symbol (b) stays active.

LED (c) keeps flashing.
4 Alarm is acknowledged (d).

Relay (b) and symbol (b) are reset.

LED (c) is off.
1 2 3
a
b
c
d
4
CAUTION
If the alarm is set to Off, an alarm condition will not be
shown by the LEDs, asserted relays or the fieldbus
output!
!
NOTICE
The hysteresis function defines an interval where a
triggered relay maintains its status until the gas
concentration is outside the defined interval. This
prevents relays from chattering at an alarm set-point.
Example: A2 at 40 % LEL Methane
Hysteresis: 3 % LEL
Alarm asserts at
≥
40 % LEL
Alarm de-asserts at
< 37 % LEL(= 40 % LEL - 3 % LEL)
i i