A branched system for measurements of the slow-variable forces using a strain gauge method

The branched measurement system described is used for measuring strain forces in roof bolting bolts used in hard coal mines. The system performs measurements in difficult industrial conditions when measurement points are scattered and hardly accessible, and in hostile environmental conditions (high humidity, dust, high salination, and methane hazards). It is adapted to continuous, long-term and multipoint automatic force measurements using strain gauges. The measurement system allows updated registration of normal and emergency loads on the bolt rods and also monitoring of the measurement circuits with failure signalling.