Digital pressure gauge series DMU is a battery portable service and shop device with a broad utilization in the industry, power engineering, heat technology, sanitary technology, air conditioning technology, laboratories, etc. Its assets become apparent namely in comparison with the liquid pressure gauges (U-pipes). This device is manufactured in several variants with regard to a method of the pressure measurements:
1. DMU - R - relative for underpressure and overpressure measurement
2. DMU - A - absolute, especially for barometric pressure
3. DMU - D - differential
4. DMU - P - differential on high static pressure
5. DMU - T - same as P with built-in three-way valve
6. DMU - S - for connecting exchangeable pressure transmitters
In all cases, it is permitted to measure both gaseous and liquid non-aggressive media, but the devices for a range 100 Pa allow measuring the non-aggressive gases only. This device is installed into a plastic ABS case. It is controlled by means of the push buttons placed on the foil keyboard. They switch on/off the device, start the possible zero correction up and switch the time filter on, which enables to read a mean value of the input pulsating pressure. Outlets for the quick couplings serve for connection of the media pressure. When measuring pressures less than 100 kPa, it is possible to connect the measurement hoses with the inside diameter 5 mm directly to these outlets. The device back side is fitted with a magnetic foil for its fixing on a ferromagnetic flat surface.
Digital value of the pressure being measured is shown on the 3.5digit LCD display. This value is displayed in kPa with resolution 0.1 % of the nominal range. The positive value coresponds to a positive pressure and the negative value to a negative pressure. As for the difference measurement, the positive value corresponds to a higher pressure in the positive pressure inlet. This device is capable to measure the pressure up to 200 % of the nominal pressure range.
To a special order, it is possible to fit the device with an analogue output with a nominal range 1 V. While measuring with an external pressure probe, the decimal point position is set up automatically according to the connected probe range.
It is also possible to agree a delivery of the DMU devices calibrated in the different pressure units.
You put the device into operation by pressing the pushbutton „ON-OFF“. In the event of the insufficient battery voltage, there will occur a symbol „LO BAT“ on the display. The battery shall be replaced in this moment because the measured results might be skewed. After replacement of the battery, always switch on and off the device by pressing the pushbutton „ON OFF“. After a short stabilization of the measurement circuits, it is possible to reset the value display in case of need. After replacement of the measurement probe in the DMU-S device and after the battery replacement, we recommend resetting always the value. If a zero pressure in the inlet is assured, start a reset routine by pressing the pushbutton “NUL”. This operation takes several seconds and its running is indicated by flickering of all decimal points. Never start the reset during your measurement.
If you need to switch on a time filtration of the signal being measured, you shall hold the pushbutton “NUL” pressed with the device switched off and then to switch on the device by pressing the pushbutton „ON-OFF“. Functioning of the filter is signaled by flickering of the colon between the second and third digit on the display. You can cancel this function by repeated switching on and off the device, but without holding the pushbutton “NUL” pressed.
If the DMU device is fitted with the analogue output, you can connect the data register or recorder to this output, or to connect it to the computer converter card. Input resistance of the follow-up equipment should be greater than 10 kohm. The output is resistant against the permanent short circuit.
