Contactor with loop power supply for monitoring current or voltage signals

The RTA421 contactor monitors industrial processes for safe operation. The unit analyzes current (0/4…20 mA) and voltage signals (0/2…10 V) and switches two independent output relays if the values either exceed or undercut the preset alarm set points. On the display both limit values are indicated in parallel. The bar graph informs on the connected signal at any time. Applications include pump control in the waste water industry. Level measurement in silos can be economically achieved.