Sporadic interferences in the industrial data communication are mostly caused by compensating currents produced by high-frequency shield currents. Faults in the fieldbus are often searched directly in the bus system and mistrust in the installation arises. Through measuring the compensating currents of the shield of the data cable it becomes clear that the fieldbus is not the reason but represents the “aggrieved party”. It is now essential to detect the initiator and to take the accordant countermeasures.
The leakage current clamp EMCheck® LSMZ I is especially designed for the measuring of leakage and shield currents in the frequency band of 50/60 Hz as well as 5 Hz – 1 kHz. The adjustable measuring range is arranged in levels from 30 μA – 100 A, whereupon the lower range is of special interest for the shield current measurement of the data cable.
Highlights LSMZ I Leakage Current Clamp
- Measuring leakage and shielding currents
- Adjustable measuring range
- Localising insulation faults and unwanted shutdown of earth-leakage circuit breakers
- All the features of a multimeter clamp
- Continuous measurements by hold functions
- Convenient measuring in unfavourable installation locations
Leakage current clamp – function & guideline
The EMCheck® LSMZ I is characterized by a large opening (2,8 cm) for the cable to led through, so that a comfortable measurement is also possible in unfavorable installation situations. Through the holding function it is possible to perform permanent measurements such as maximum currents.
By the experiences of Indu-Sol GmbH, a shield current of < 40 mA was proven justifiable, independently from the machine specifications. A statement according to the level should be made in connection with the adjusted frequency range, to carry out the correct actions in terms of a reduction of shield currents.