Nilsson 400

The Nilsson 400 Soil Resistance Meter can be used with the kit to provide soil resistance values read directly from the analog dial of the meter. No calculations are necessary. The wide-range, high sensitivity meter has large, 100-division dial for easy readability and 8 ranges from 0.1 ohm to 1.1 megohm.

The Nilsson Model 400 Soil Resistance Meter js a 4 terminal, null balancing ohmmeter. It measures resistance from .01 ohm to 1.1 megohms. The Model 400 can be used as a 4, 3, or 2 pin device for soil resistance measurements, or can be used with a soil box or a single probe.

The unit generates a low voltage 97 Hz square wave current between the C1 and C2 binding posts. The detector, whose input is connected between the P1 and P2 binding posts is only sensitive to 97 Hz, and so is not affected by stray A.C. or D.C. currents. The detector senses the voltage drop between the P1 and P2 binding posts, compares it to internal standard resistors, and indicates a difference on the null detector. When the null detector is balanced, using the ran9e switch and the dial, the resistance in ohms between P1 and P2 is the dial reading multiplied by the range switch position.

MC Miller’s “Large Soil Box”, which has a 270 ml (270 cubic cm) volume is compatible with 4-Terminal Resistance Meters such as the Miller 400A, the Miller 400D, and the Nilsson 400 Resistance Meters.

MC Miller Soil Boxes can be used to satisfy either the 4-electrode method (ASTMG57 Standard) or the 2-electrode methods (ASTM G187 or AASHTO T-288 Standards).  For the 2-electrode method, the two interior pins are removed which changes the multiplication factor from 1cm (for the 4-electrode method) to either 0.67cm for the small box or to 0.57 cm for the large box.

Construction Materials:

• •  Plexiglas body with rounded corners for easy cleaning. •  Stainless steel current distribution plates and removable brass pins (potential measurement pins).

Critical Dimensions (for 4-electrode method, i.e. the two interior pins are in use):