Environnement Envea MIR 9000, Техническое руководство, Страница: 74 / 212

Environnement
S.A
MIR 9000
Duplication prohibited
3–30
JULY 2009
For the analog inputs, it is necessary to specify the MUX channels used for acquisition ( MUX Channel
parameter). Channels 17 to 19 or DTP1 to DPT3 are reserved for this application. The connection is
then made direct to the interface 2 board.
The linearity parameters ( Ax2 , Bx and C ) allow converting a voltage signal (0-2.5 volt) into a
measurement (0-200 °C for example).
CAUTION: The maximum voltage on these analog inputs is 2.5 volts.
The calculated values are determined from the analog inputs. Therefore, it is not necessary to specify
a MUX input or linearization.
For the pressures measured in hPa and the temperature in °C, the chimney flowrate is calculated in
KNm
3
/h (in thousandths of normal cubic metres per hour) and the speed in m/s (in metres per
second).
The units and display formats for each parameter should be configured in the “ Configuration /
Signal-Ranges-Units” menu.
The lower part of the screen is common to each of the parameters.
The K Pitot coefficient corresponds to the coefficient of the Pitot tube itself in use (usual coefficient:
0.75).
The Mass vol. parameter corresponds to the volumetric mass of gas (usual coefficient: 1.293 g/l).
The Chimney parameter corresponds to the diameter of the chimney, in metres.
The Backblow parameter defines the frequency of back-blowings per hour (01h, 03h, 06h, 12h or
24h); the duration is defined by the Time parameter.
The measurements are blocked during back-blowing and a stabilisation period equal to the duration of
the back-blowing.
The back-blowing command is transferred to the EVC5 connection of the TIG2 board.
For a nil frequency (00 h), the measurements are blocked during each of the back-blowing cycles of
the MIR. This function enables back-blowing the Pitot tubes via a command of the SEC Probe.
Output Unit: MUX channel
Chimney flowrate Fext – KNm
3
/h Calculated value -
Chimney temperature Text - °C Analog input 17
Chimney pressure Pext – hPa Analog input 18
Gas speed Sext – m/s Calculated value -
Pitot pressure Pdif – hPa Analog input 19
Figure 3–3 – Configuration of the five DTP parameters
STOP