Seitron 7899 Mode D'emploi page 4

lasts 45 seconds.
During this phase the instrument displays the word 'HEAT' and
the remaining time before the end of it.
When the pre-heating is terminated the auto-zero phase is
initiated, lasting 6 seconds and identified with another short
beeping sound. Once also this is terminated, another
prolonged beeping sound indicates the full functionality of the
instrument.
During normal operation, while no gas is detected, the
instrument will issue a short beep every 2 seconds.
In case a leakage is detected, the rate of the sound will be
higher accordingly to the measured concentration.
The instrument is factory set with the auto-shut-off feature
turned on and the relevant time set to 10 minutes.
This means that the instrument will automatically turn off after
ten minutes from turn-on.
A temporary turn-off for this feature (until the first manual turn-
off) can be accomplished by pressing the '
4 seconds during the turn-on phase. In order to turn the
instrument off please press the
confirmed with three short beeps issued in sequence.
' >0< ' AUTOZERO key.
When this key is pressed (an the instrument is on) the auto-
zero procedure is initiated.
As previously explained, the auto-zero time is 6 seconds long,
stressed with a beeping sound and with 4 '0.000' digits flashing
on the LCD.
During this phase the instrument samples the actual gas
concentration and assumes that as a zero baseline for any
following measurement.
When this phase is terminated, the instrument will sound a
prolonged beeping sound.
AUTOMATIC Zero drift adjustment
In absence of gas the instrument continuously checks its zero
level and performs an automatic drift adjustment, provided the
variation is maintained within some limits.
This compensation is transparent for the user and it is
performed every 2 seconds in order to compensate any
possible sensor drift mostly due to temperature variations.
When the sensor detects the presence of gas it abandons this
compensation procedure and switches to the gas detection
operation.
' H ' Hold key
When the 'H' key is depressed, the 'HOLD' mode is started,
during which the actual read value is 'frozen' on the lower 4
digits display. When in this mode the instrument truns the label
'HOLD' on and issues a short beep.
During this mode the upper 4-digits display will keep on
showing the current measured concentration value (thus
following the concentration variations), meanwhile the lower 4-
digits display shows the 'frozen' value.
If the 'H' key is again depressed the instrument will exit from
the 'HOLD' mode, sounding a short beep as a confirmation.
'UNIT' Measurement Unit Key.
When this key is depressed the measurement unit in which the
display reading is expressed is selected.
Every time the 'UNIT' key is further depressed, the instrument
will cycle among the available measurement units, according
to the following sequence (Starting with the unit currently
selected):
=> ppm => %vol => % L.E.L. => ppm =>
every time the unit is changed, the choice is automatically stored
in the instrument memory, so that during the next instrument turn
-on this will be the default unit.
' SET ' key
When this key is kept depressed for at least 3 seconds a mode is
entered in which the user can set the generall parameters for the
instrument operation.
These parameters are three and the user can switch between
' key for at least
' ' key: the action is
one and the following by pressing the 'SET' key.
Once a parameter is selected, its value can be modified with the
following keys:
'FUNC' Key: Increases the value (if numerical) or switches
between On and Off cyclically (if non-
numerical).
'UNIT' Key: Decreases the value (if numerical) or switches
between On and Off cyclically (if non-
numerical).
Parameters which can be adjusted are the following:
P1: Acoustic Feedback Enable/Disable
This parameter is identified with the label 'SEt 1'.
Its value enables or disables the internal buzzer for the acoustic
feedback.
Press the 'UNIT' or the 'FUNC' key to change the actual value.
The instrument is factory set with the feedback enabled
(Set 1=On).
P2: Auto-Shut-Off Time.
From parameter 'Set 1' if the key 'SET' is further depressed
once, the user gets access to parameter 'SEt 2' which allows to
change the auto-shut-off time. The 'UNIT' key decreases the
current value, meanwhile the 'FUNC' key increases it.
The allowed values for this parameter are in the range 1 .. 30
minutes in 1 minute steps.
In order to disable this feature (instrument turned on until a
manual turn-off) the user must increase or decrease the
parameter value until the label 'OFF' is set.
P3: Buzzer on Alarm Enable/Disable.
From parameter 'Set 2' if the key 'SET' is further depressed
once, the user gets access to parameter 'SEt 3' which allows to
enable or disable the buzzer sound in case of an alarm.
Press the 'UNIT' or the 'FUNC' key to change the actuall value.
The instrument is factory set with the alarm buzzer enabled (Set
3=On).
From this parameter a further action on the 'SET' key results in
quitting the parameters configuration mode, together with the
storage in the instrument memory of the preferences just set.
OVERRANGE FUNCTION
This function, active any time, continuously checks for the
measured concentration to remain within the instrument full
range limits. Should the full range value be exceeded, the
internal buzzer will start beeping at the maximum repetition
rate and, at the same time, the 'ALM' symbol will be turned on
and the lower display will show the label 'OFL' (overflow).
LOWBATT FUNCTION
The instrument continuously analyses the battery level and, in
case this is found below a certain value, the low-level battery
icon ' ' is shown in the upper right side of the display.
When this symbol is turned-on, the instrument is still perfectly
operational.
After this, when the battery voltage falls below another critical
level, the words 'Lo bAtt' are shown on the display and the
operation of the instrument is stopped: the only action allowed
to the user is the turn-off.
When the instrument is further turned-on, if the supply voltage
is in the valid range, all the functions are enabled again.
For batteries replacement please follow the directions
explained in the paragraph 'Preliminary Operations'.
BUZZER
This instrument features an internal buzzer for both the
purpose of an acoustic
concentration and for an acoustic feedback on some user
actions.
When the instrument is detecting a gas concentration higher
than zero, the repetition rate of the 'beeps' increases according
to the concentration level.
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indication of the measured