AL-3 Monitor Optimises Analogue Signalling Devices
IFM Electronic has introduced the AL-3 monitor, which complements analogue signalling devices by allowing the user to set switchpoints and compare or combine values and scaling ranges. The AL-3 monitor is a programmable, two-channel analogue threshold relay with two inputs for analogue standard signals (0/4...20 mA). It picks up the current signals on separate inputs, compares them with the set limit values and switches the outputs according to the set switching functions. The input signals can be scaled to the measuring range of the sensor or transmitter so the measured values are indicated on the front display corresponding to their physical unit. The AL-3 features an output relay with changeover contact and a transistor output for each channel. The user can monitor values that exceed or fall below the limit values and window function. In the comparator operating mode, a differential pressure can, for example, be determined from the two input signals, monitored and provided as an an