DMU-JB - digital pressure meter / manometer - ATEX

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Basic technical information of pressure transmitter

* valid for devices calibrated in Pa or kPa
I M1 Ex ia I Ma
II2G Ex ia IIA T4 Gb
At the customer´s wish it is possible to secure a metrological verification of the pressure meters at an accredited Calibration Service Centre.

Instructions for use

• In the medium with explosive gas atmosphere or occurrence of methane and/or flammable dust, it is prohibited to take the gauge DMU out of the leather casing!
• The instrument is started up by a short pressing of the “ON-OFF” button. In case of insufficient voltage of the battery, the sign “LO BAT” will appear on the display. In such a situation the battery must be changed because it could cause distortion of the measured results. After the battery is changed, always switch on and off the instrument using the “ON-OFF” button. After a short setting of the measuring circuits, it is possible to carry out resetting the data if necessary. After transition into a medium with significantly different temperature, it is necessary to avoid dewiness of the instrument and let it thermally stabilize for a longer time. We recommend carrying out resetting always when the battery is changed. When zero pressure difference on the inputs is secured – by disconnecting all tubes and in the area without distinctive flow of the surrounding air – the resetting routine is started up by a short pressing of the “NUL” button, position 6. This process lasts for a few seconds and its course is indicated by flashing of all decimal points. Never start up resetting during measuring!
• If you need to switch on time filtration of the measured signal, you must hold the “NUL” button with the instrument switched off and switch of the instrument by pressing the “ON-OFF” button. The operation of the filter is signalized by a flashing colon between the second and third figure on the display. Cancelling of this function is made by repeated switching off and on of the instrument without holding the “NUL” button. The time constant of the filter is fixed and cannot be changed.
• While measuring at the range 100Pa, we recommend to measure at the defined position of the gauge where resetting has been made to eliminate the position error which can reach up to 1% of the nominal range. At higher ranges, this error is insignificant.
• Before the gauge is connected to the pressure circuit, it is necessary to check whether the measured medium does not attack the used materials, ie. silicon, duralumin, brass, plastic material polyetherimid and fluorine-silicon sealing. Air, nitrogen, etc. are convenient to these requirements without any problems. Avoid penetration of liquid to the measuring system of the instrument! Though there is not a danger of immediate damage conversely, especially measuring of low pressures is slow, distorted and showing significant hysteresis thanks to the effects of capillary forces. If liquid penetrates to the measuring input, avoid its freezing inside the measuring system. Let the instrument dry at normal temperature for several days or send it to the producer for repair. Never try to clean the pressure input by means of wire or any other sharp object! There is a danger of destroying the measuring membrane!
• It is also necessary to check whether the pressure range of the instrument, stated on the label, position 4, corresponds with the measured pressure. At such an overload of the instrument up to the Maximum overload overpressure, stated in the Technical data chart, the producer secures maintaining of measuring accuracy. When this level is exceeded up to the Nedestr. pressure value, the producer guarantees that the measuring sensor will not be destroyed, but it is recommended to carry out a checking calibration.