LOOP CONTINUITY RELAYS
GM 420
The GM420 series loop monitor is designed to monitor the resistance of PE conductor connections in AC systems and in de-energised systems. The extraneous voltage Uf between the terminals E and KE must not exceed AC 12 V. The ohmic resistance of the conductor loop and the AC extraneous voltage Uf, if existing, will be indicated on the display. The currently measured value is continuously indicated on the LC display. If the measured resistance value increases above the set response value, the alarm will be activated and stored. Adjustable time delays allow installation-specific requirements to be considered
RM475LY
The devices of the RM475 series in conjunction with a terminating device are designed to monitor a closed and voltage-free loop for interruption (series resistance) and for short-circuit (cross resistance). The RM475 version has a continuously set response value for series and cross resistance. The response time is max. 1 s.
The response value for the series resistance of device version RM475LY can be adjusted between 50…500 Ω. The response value for the cross resistance for this version, however, is continuously set, too. The response time can be set between 1…10 s.
