3. Current Measuring Station TIS-2.
In 2004-2005, the laboratory developed and constructed a prototype model of the current measuring station TIS-2. The urgent need for it emerged when we no longer could ensure the synchronous operation of the sounding electropulse system ERGU-600 and measuring receiving stations during electromagnetic monitoring of the Earth’s crust. In the past, the synchronization of ERGU-600 and receiving stations had been realized by ЧЗ-57 synchronometers having high accuracy of time indications ensured by the daily adjustment of these indications to the signals of special radio stations (unified service of precise time). Since 2004, the network of these stations has stopped its operation due to the all-round introduction and use of GPS system which ensures high precision of time indications in almost every point of the world.
TIS-2 (fig.5) is designed to work as a part of measuring system consisting of ERGU-600 generating plant and a network of special receiving sites equipped with electric measuring stations (IS-2) which ensure active electromagnetic monitoring of the Earth’s crust by the method of time-domain electromagnetic sounding. Current station TIS-2 is a part of electromagnetic prospecting generating plant ERGU-600.
Fig. 5
In addition to equipment present at the ERGU, the TIS-2 ensures:
- accurate adjustment of frequency of clock-signal generator of the ERGU-600 synchronization system by signals of GPS-receiver,
- start of ERGU-600 in preset time according to signals of GPS-receiver,
- amplification and analogue filtration of signals of current sensor of ERGU-600,
- registration and digital processing of signals of current sensor,
- visualization of received information on visual display and storing of it on a hard disk of PC.
Fig.6 shows TIS-2 structure.
Fig. 6
GPS – GPS-receiver;
УИ – measuring amplifier;
К – master micro-controller;
СОМ – buffer for serial port (RS-232);
БП – power supply unit;
ГУН – clock-signal generator controlled by voltage (16384 kHz);
ЦАП – digital-analog converter;
АЦП – analog-digital converter;
УГР – junction of galvanic separation;
ПК – personal computer.
Major specification of TIS-2:
- Range of measured currents (current sensor output voltage)...……5 ÷ 1000 А, (0,005 ÷ 1,0 V)
- Bandwidth of measuring channel by level minus 3 dB...................................................0 ÷ 75 Hz
- Relative error of current measurements (voltage) of value of 600 А, (0,6 V),
no more than.......................................................................................................................0,1 %
- Sampling frequency of measured signal ................... (50, 100, 200, 400, 800 Hz) ± 2,5•10-7 %
- Capacity of analog-digital converter ........................................................................../...... 16 Bit
- TIS-2 output pulse repetition rate for external synchronization
of ERGU-600................................................................................................10 ± 2,5•10-7 % kHz
- Time accuracy of formation of triggering signal front for ERGU-600 ............................... ± 10 μs
- Power consumption, no more than ..................................................................................... 20 W
