Displaying Information; 8 Calibration; Test Gases; Preparation Of Calibration - Dräger PointGard 2000 Série Mode D'emploi

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en Calibration

7.6.4 Displaying Information

Select the appropriate menu item in the Information menu:
Instrument
Warnings Displays warning messages in plain text
and the corresponding number.
If there are several warning messages
available, there is an indicator (e.g. 1/3 =
Screen 1 of 3).
Faults Displays fault messages in plain text and
the corresponding number
If there are several faults, there is an indica-
tor (e.g. 1/3 = Screen 1 of 3).
Device flag This function displays warning and fault
codes as a table. If all codes are 00 there
are no warning or fault messages available.
Modules Displays an overview of the installed hard-
ware modules. To access detailed informa-
tion select the appropriate module.
= installed modules
= not installed modules
Sensor
The sensor vitality is displayed in %.
1)
Vitality
Changing the sensor is recommended with
a vitality < 25 % by Dräger.
Last cal. The calibration date, unit, gas and concen-
date tration of the last calibration are displayed.
Next cal. Displays the next calibration due date.
date
Sensor The current and the highest sensor tem-
tempera- perature is displayed.
1)
ture
Data logger
Logger Displays the data logger status (active or
status non-active)
Graph Displays the history of the past 15 minutes
on a time/concentration graph.
1) Function only available with diagnostic dongle.
8 Calibration
A calibration checks and adjusts the measurement accuracy
with a known test gas concentration. First the zero point of the
sensor and then the sensor span is calibrated. Calibrations
have to be performed on a regular basis. The length of
calibration intervals depends on the ambient conditions in
which the sensor is operated.
Ambient conditions and aging cause sensor drifts. Sensor
drifts have a negative impact on the measurement accuracy.
Calibrations restore this accuracy. Depending on the severity
of the drift shorter calibration intervals have to be established.
To evaluate the ambient conditions of a new installations,
shorter calibration intervals with documentation of the drift
should be established. The plant operator should establish
customized calibration intervals with the obtained data.
16
Under normal conditions, Dräger recommends the following
1)
calibration intervals :
– Electrochemical sensors (EC): 6-12 months
– Catalytic sensors (CAT): 4 months
– Infrared sensors (IR): 6-24 months
8.1

Test gases

For test gas properties (e. g. humidity, concentration) refer to
the corresponding sensor data sheet.
Test gas humidity is irrelevant for O
Depending on the type of calibration different test gases are
used.
Zero gas
Zero gas is a test gas to calibrate the zero point. If ambient air
is free from interfering impurities and measured gas, it can be
used as zero gas. For O sensors, nitrogen (N
2
Calibration gas
Calibration gas is a test gas to calibrate the sensor sensitivity
during span calibration. Calibration gas is a known
concentration of the measured gas diluted with clean air or
nitrogen. For O sensors no calibration gas is needed, as
2
oxygen from ambient air is used.
8.2

Preparation of Calibration

WARNING
Health hazard due to test gas
Inhaling test gas may risk health or lead to death.
► Do not inhale test gas.
► Observe risks and security statements related to the test
gas (Refer to data sheets and instructions figuring on
calibration devices).
CAUTION
Triggering alerts by test gas
Applied test gas may trigger alerts.
► Make sure that test gas is no longer applied after
calibration.
Prerequisites:
– Sensor has finished the warm-up phase
(6 Commissioning of the instrument).
– Date and Time are set (11.2 Setting date and time).

8.2.1 Preparing calibration set-up

For all transmitters except PointGard 27x0 IR:
Refer to the following figure.
1) Observe sensor data sheet and sensor IfU
2) For applications in line with EN45544-1 the calibration interval must
not exceed 6 months.
Instructions for use
2)
2)
sensors.
2
) is used.
2
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Dräger PointGard 2000 Series