The ADVANCED RM15-D is designed for professional or research purposes use where greater accuracy is required, and includes all the features of the RM15 BASIC plus many more. The RM15-D ADVANCED provides an additional current range of 10mA and 100 V output, giving a maximum logged resolution of 0.0005 ohm. The 10 mA range can be used to further improve the noise rejection of the BASIC instrument and also provide improved accuracy with wider probe array spacings--this is because the system gain does not need to be so high, and hence measurement errors will be reduced. The 100 V output gives extra compliance, especially useful in dry conditions at higher currents, when it will improve the reliability of auto-logging and enable readings to be taken which may not otherwise be possible with a BASIC instrument. There is a choice of operating frequencies: 35 Hz, 85 Hz or 137 Hz, with the lower frequency providing the greatest accuracy for conventional four probe arrays, due to reduced capacitive and inductive errors.
Readings are stored in a non-volatile memory which may be partitioned into grid sizes of 10m, 20m or 30m, with reading interval being either 1m or 0.5m. The data logger keeps track of survey position for both zig-zag and parallel traverses and displays current grid, line number and line position. An additional survey tracking parameter is introduced when using the MPX15 multiplexer. Incorrect readings may be deleted singly, or as a complete line, with one keystroke. A dummy reading can be inserted if a physical obstacle prevents a true reading being taken or a line may be completed with dummy readings, again with one keystroke. A mirror image "complete" line key is also provided for zig-zag surveys when part of the standard grid cannot be surveyed. An ENABLE LOG key controls data logger functions thus preventing accidental loss of data.
Due to a special current sense circuit in both the BASIC and ADVANCED RM15-D logging can be automatic with any probe configuration that has a current probe mounted on the mobile frame, for example the Twin array. The operator simply inserts the probes of the mobile frame into the ground and the RM15-D will determine when the reading has settled, log it, and then give an audible beep to tell the operator to move onto the next reading. This mode of operation greatly reduces errors and operator fatigue, leading to a considerable increase in area survey speed - typically 400 readings may be taken in about 12 minutes. Auto-logging with the MPX15 Multiplexer enables large data sets to be acquired very rapidly.
The RM15-D requires a probe array to be able to take measurements and software to process and display the data. Accessories presently available include the PA3 Probe Array, the PA20 Probe Array, MPX15 multiplexer and MSP40 Mobile Sensor Platform. The PA20 and MPX15 are especially recommended for detailed and rapid area surveys. An anti-vibration mounting kit is also required if you wish to mount the RM15-D on a PA20 frame. Program Geoplot 3.0 is recommended for data transfer, processing and presentation of the data. See Recommended RM15 Systems for further details. The RM15-D is supplied as standard with an instruction manual, battery charger, data dump cable and a robust executive style carry case.
Upgrading an RM15 to and RM15-D Back to top of page