Measurement modes | Apparent resistivity, resistance, voltage (SP), induced polarization (IP), battery voltage |
Measurement range | 400 kohms to 0.1 milliohms (resistance) 0-500 V full scale voltage autoranging. |
Measuring resolution | Max 30 nV, depends on voltage level |
Screen resolution | 4 digits in engineering notation. |
Output current | 1-2-5-10-20-50-100-200-500 mA. |
Output voltage | The user can switch between high and low voltage limit for the transmitter (800 Vp-p or 320 Vp-p voltage limit). Actual electrode voltage depends on transmitted current and ground resistivity. |
Input gain ranging | Automatic, always uses full dynamic range of receiver. |
Input impedance | >20 Mohms |
Input voltage | Max 500 V |
SP compensation | Automatic cancellation of SP voltages during resistivity measurement. Constant and linearly varying SP cancels completely. |
Type of IP measurement | Time domain chargeabilitiy (M), six time slots measured and stored in memory |
IP current transmission | ON+, OFF, ON-, OFF |
IP cycle times | 1 s, 2 s, 4 s and 8 s |
Measure cycles | Running average of measurement displayed after each cycle. Automatic cycle stops when reading errors fall below user set limit or user set max cycles are done. |
Cycle times | Basic measure time is 1.2, 3.6, 7.2 or 14.4 s as selected by user via keyboard. autoranging and commutation adds about 1.4 s. |
Signal processing | Continuous averaging after each complete cycle. Noise errors calculated and displayed as percentage of reading.Reading displayed as resistance (dV/I) and apparent resistivity (ohmm or ohmft). Resistivity is calculated using user entered electrode distances. |
Noise suppression | Better than 100 dB at f>20 Hz Better than 120 dB at power line frequencies (16 2/3, 20, 50 & 60 Hz) |
Total accuracy | Better than 1% of reading in most cases (lab measurements). Field measurement accuracy depends on ground noise and resistivity. Instrument will calculate and display running estimate of measuring accuracy. |
System calibration | Calibration is done digitally by the microprocessor based on correction values stored in memory. |
Supported configurations | Resistance, Schlumberger, Wenner, dipole-dipole, pole-dipole, pole-pole, azimuthal, mise-a-la-masse, SP (absolute) and SP (gradient). |
Data storage | Full resolution reading average and error are stored along with user entered coordinates and time of day for each measurement. Storage is effected automatically. |
Memory capacity | More than 3000 measuring points can be stored in internal memory. |
Data transmission | RS-232C channel included to dump data from instrument to PC on user command. |
Automatic multi-electrodes | The MiniSting is designed to run dipole-dipole surveys completely automatic with the optional Swift Dual Mode Automatic Multi-electrode system (patent 6,404,203). The MiniSting/Swift can run any other array (Schlumberger, Wenner etc.) by using special user programmed command files. These files are created in an MS DOS type computer and downloaded to the MiniSting RAM memory and are later recalled and run in the field. Therefore there is no need for a fragile computer in the field. |
User controls | 20 key tactile, weather proof keyboard with numeric entry keys and function keys. On/Off switch Measure button, integrated within main keyboard. LCD night light switch (push to illuminate). |
Display | Alphanumeric LCD display (4 lines x 20 characters) with night light. |
Connectors | 4 banana plug, pole screws for current and potential electrodes. 10-pole KPT connector for external power, RS-232C and synchronization connections. |
Power supply, field | 12/24 V DC external power, connector on front panel. Maximum power output is increased when using 24V supply. |
Power supply | 12V, 4.5 Ah NiMH built-in rechargeable battery. External power connector on front panel, the instrument automatically selects external battery if present. |
Operating time | Depends on conditions, internal circuitry in auto mode adjusts current to save energy. At 20 mA output current and 10 kW electrode resistance more than 2000 cycles are available from a fully charged battery pack. |
Battery charger | Dual stage charger with switchable input (115/230 V AC @ 50/60 cycles) |
Weight | 6.6 kg (14.5 lb.) |
Dimensions | Width 255 mm (10"), length 255 mm (10") and height 123 mm (5"). |