RM85 Resistance Meter
from Geoscan Research

The RM85 Resistance Meter is ideally suited or for rapid near surface area or vertical profile measurements. The instrument measures and records resistance vales which provide the operator the flexibility to deploy any conceivable Quadrature array, then convert the data to resistivity during processing. The instrument also includes pre-programmed arrays for instance Pole-pole, Double- Dipole, Wenner Schlumberger and Gradient.

RM85 console. Image courtesy of Geoscan Research.
RM85 console. Image courtesy of Geoscan Research.

Within our rental pool we offer the RM85 Advanced with multiplexer card and GPS compatibility. Common accompanying accessories include the PA20 frame with a choice of 0.5m, 1m or 1.5m beam and sounding cables. The RM85 Advanced offers a wider current range (from 0.1mA to 10mA) and a maximum output of 100V, to allow operation in more demanding situations. A half current setting (Compliance Boost) allows the user to optimise signal to noise ratio against probe contact resistance.

The multiplexer allows the system to be programmed with up to 16 measurement configurations permitting both sequential depth measurements and parallel measurements to be recorded automatically.

The enhanced system specifications and wide suite of accessories means the RM85 lends its self to a wide verity of near surface geophysical applications such as Archaeological Prospection, Agricultural studies, Environmental and engineering applications.

Product Dimensions

Physical Dimensions (L x W x H) Weight
RM85 Resistance Meter (instrument only) 20cm x 12cm x 9cm 1.35kg (console only)

Technical Specifications

Output voltage: 50 or 100V.
Constant current ranges (p-p): 10mA, 5mA, 1mA, 0.5mA ,0.1mA & 0.05mA.
Resistance ranges: 2, 20, 200, 2000, & 20,000Ω.
Logged resolution: 0.0005, 0.005, 0.05, 0.5 & 5Ω.
Operating frequencies: 17.5, 20, 22.5, 35, 40, 72.5, 80, 85, 90, 122.5, 137, 140, 142.5 Hz, User Defined.
Probe mode Auto-Log Delay times: 20, 200, 300, 450, 600, 800, 1000, 1200 ms (faster with Speed Boost).
High Pass Filter: Off, 0.05, 0.16, 1.6, 8, 13 & 15 Hz.
Memory capacity: 491,200 readings, without GPS.
Grid dimensions: 10, 20, 30, 40, 50, 60, 100m (length and width independent).
Sample Interval: 0.0625, 0.125, 0.25, 0.5, 1m.
Communications: USB (2.0) and RS232 at up to 115200 baud (RS232 only for GPS).
Power: NiMH battery pack, 4 hours charging time.


Contents Dimensions (L x W x H) Weight
PA20 Frame and remote cable
175cm x 90cm x 30cm 28kg
RM85 console and cables
50cm x 23cm x 40cm 6kg
Ski tube
0.5m, 1m and 1.5m beam & 6 Electrodes
115cm x 60cm x 25cm 10kg