EM-M82A Line guard

EM-M82A is a control unit for controlling and watching automation devices which have terminal impedance in between 15-300 ohm. Suitable load can be a solenoid, valve, contactor or resistance. The unit is configured with switches and prog. button. The range selection is made with switches. After the right range is set the device can be "learned" to recognize the normal line impedance by pushing the prog. button. The unit will watch the line impedance in "on" and "off" situation. The device have possibility for special learning if load is unlinear. in this case the learning would make individually for "off" and "on" situation.If the unit detects impedance change more than +100% or -50% , the device will give a "fault" alarm. The unit also watches over the function of its own control relay. If the control ( input ) status and line voltage are in contradiction, unit will give an alarm just as in "fault" situation. The fault output relay is normally energized, so if power supply disappears the unit will give "fault" alarm also. EM-M82A has an input for controlling the line on/off. The control relay can drive the loads up to 1.5A continuous current. The relay has its own snubber circuit for driving inductive loads too. The other end of control relay coil is normally connected to supply 0V, but it can all so be separated from supply if there is a need for isolation between control and load circuitry. The unit is protected against short circuit and over voltage spikes on load line and against supply voltage reversing.