ENMET OMNI-4000 - Manual (Page 41)

OMNI-4000 S/N 6705 and above ENMET Corporation
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3.0 Maintenance
3.1 Scheduling OMNI-4000 Maintenance
The sensor responses of an OMNI-4000 should be checked at least every thirty days, by exposing the sensors to
appropriate gases and monitoring for expected instrument response. It is recommended that all MOS block and
combustible LEL sensors of a OMNI-4000 instrument be completely recalibrated at least every ninety days, and the
Smart Block toxic sensors every six months, utilizing the procedures given in this manual. Good practice dictates
more frequent checking and calibration under particularly dangerous conditions and conditions of heavy usage. Some
instrument users check sensor responses at the beginning of every period of usage, such as every shift. National, state,
local, or company specifications may dictate minimum calibration intervals.
3.2 The Maintenance Menu
3.2.1 Accessing the Maintenance Menu
When the device is ON, the main menu can be accessed in either one of two ways:
ƒ After opening the enclosure on the circuit board side and positioning the switch towards the center of the device.
See Figure 3-1, right side.
ƒ Without opening the enclosure by inserting the special plug in the DIN socket located on the side of the enclosure.
See Figure 3-1, left side.
This description is given for the purposes of information only. It is recommended that the detailed instructions given
in the following chapters on maintenance be followed carefully. It is often safer not to open the enclosure and thus to
avoid any possibility of incorrectly handling any of the components.
When one of these two actions has been performed, the display shows "Programming a channel" to signal that the
Main Maintenance Menu has been accessed.
N
OTE : Insufficient battery voltage prevents access to the main menu. The operator is warned with a "Maintenance
impossible" message. It is possible to continue by connecting the charger or by changing the battery pack.
Sub-Menus
Once the Maintenance Menu appears, the first of the four menus available is displayed: "Program a sensor." Then, the
following menus are available, by using the MENU switch.
ƒ Calibrate a sensor
ƒ Replacing the explosive gas sensor
ƒ Set Date and Time
The structure of the Maintenance Menu as a flow-chart is shown in Figure 3-2. Each time that the MENU switch is
pressed, the next item is displayed; this forms a loop. To select a menu, press the ENTER switch.
3.2.2 Overview: Program a Sensor Menu
This menu is used for:
•
Selecting the channel for programming
•
Enabling or disabling the selected channel
•
Informing the operator of the sensor type and measurement range
•
For an explosive gas channel, selecting the reference gas from amongst the 27 preset gas types or entering the
coefficient for a 28
th gas
•
For an oxygen channel, programming the low and high alarm thresholds
•
For toxic channels, programming the instantaneous alarm levels