Instruction Manual
ExTox Control Units Series ET-8D and ET-4D2
Page 14 of 39
Menu Text
Selection
Function
Alarm Levels
AL1, AL2, AL3
(left column)
0 to end value
of measuring
range (MBE)
Fixes the three alarm levels and the direction of exceed-
ing for triggering of alarms.
a.
Values of alarm levels are in ascending order
(0 Al1<Al2<Al3 MBE): alarms are triggered on ex-
ceeding.
b.
Values of alarm levels are in descending order
(MBE Al1>Al2>Al3 0): alarms are triggered on un-
der-run.
c.
Alarm level 3 = 0 and Alarm level 1 < Alarm level 2
(Al3 = 0 and Al1 < Al2): Alarm 1 is triggered on un-
der-run, Alarm 2 is triggered on exceeding (window
range)
Example Methane concentration in biogas:
Alarm 1: 40 % (v/v) CH
4
, Alarm 2: 60 % (v/v) CH
4
.
Alarming is done in case the range of 40 to 60 %
(v/v) is left downwards or upwards.
Please note that all alarm levels have to differ at least
for a minimum. In case the Alarm level 3 is not neces-
sary it should be configured in case a. to the end value
of measuring range and in case b to 0. There is no eval-
uation of alarms if they are adjusted on 0.
All other constellations of parameters are rejected by
the Software when trying to store them.
If you use the Adjustment Function (see 4.6) of the con-
trol unit please pay attention to the remarks for selec-
tion of alarm levels described therein.
Mode (M,
left column)
On,
Off
Switches on or off the evaluation of channel. The status
is indicated by means of the status LED operation during
measuring operation. (On = green LED on, Off = green
LED off)
FA
0,
1
Indicates whether the alarm evaluation should be acti-
vated (1) or whether the alarms should be locked and
reset (0) in case of channel alarm.
Standard setting: 1
Attention: deviations from the standard settings should
not be performed for most of the safety concepts. Any
deviation should be assured by superior safety concepts.
Latching
AL1, AL2, AL3
(right column)
0,
1
Indicates whether the alarm is latching (1) or not latch-
ing (0). According to EN 60079-29-1, chapter 4.3.3.2
the lowest alarm shall only be configured as not latch-
ing. A not latching alarm stops if the alarm condition is
no longer present. Please keep in mind the alarm hyste-
resis (see 4.8.2). A latching alarm has always to be re-
set manually (see 5.3).
Channel Fault
(F, right col-
umn)
0,
1
Indicates whether the channel fault is latching (1) or not
latching (0).
A not latching channel fault stops if the alarm condition
is no longer present.
A latching channel fault has always to be reset manually
(see 5.3).
You can also connect ExTox smoke detectors to the ET-8D and ET-4D2 (see 10). In this
case different procedures have to be considered.
