OM 2000M/M mining ohmmeter


The OM 2000M/M™ features two measuring ranges. The first measuring range (from 0,0 to 20,0 Ω) is designed for testing and selecting a single EBC, while the second measuring range (from 0 to 2000 Ω) is designed for a blasting circuit check.

The selection of the measuring range is made automatically.

The device is turned ON/OFF by means of a magnetic key. The terminals are equipped with circular pads for quick EBC selection.

Display and accuracy

The reading is carried out through a 3½ digit, 7 segment LCD display with a decimal comma. The digits are 13 mm high, so reading the display is unproblematic even in low light environments. The display includes a battery low indication.

The rated accuracy of the OM 2000M/M within the first measuring range is 0,1 Ω and 1% (or 1 Ω) within the second measuring range. The actual accuracy is much higher.


The OM 2000M/M incorporates safety features for usage in hazardous areas such as gassy mines, as well as against unintentional activation of any type of blasting cap.

The type and level of explosion protection of OM 2000M/M means that it can be used in the underground mining and that it fulfills the most demanding requirements of intrinsic safety protection.

The maximum measuring current in short circuited terminals is less than 1 mA, while the maximum measuring current in the worst case scenario of two simultaneous independent theoretical faults does not exceed 8 mA – significantly less than “non fire” rating of any type of EBC.

Mechanical protection

The mechanical protection of the OM 2000M/M is designed so as to have extreme underground working conditions in mind. The top casing is made of thick transparent polycarbonate, the same material that military jet cockpits are made of. The clearance between the display and the casing makes it safe from the impact–deflections of the casing. The casing is water–proof sealed and tested up to an IP 67 level of ingress protection, while the electronic circuitry is cast in a monolithic block using a hard casting compound.

Maintenance and the battery life

The OM 2000M/M requires no maintenance, except the occasional cleaning of coal dust and mud from the terminals and visual check. The current consumption of the device is very low — a single 9 V alkaline battery provides more than 100000 (one hundred thousand! measurements) and therefore the battery is replaced only when it’s shelf life expires.