Voltage surge protection.
Scheme analogue of the device protection against voltage surges “Digital barrier”.
The proposed microcontroller device is designed to protect electrical equipment and equipment connected to a 220 V network. In the event of an emergency, when the mains voltage goes beyond the permissible limits, the protection device disconnects the load.
At the same time, the device displays the value of the mains voltage on the LED 7 “segment 3” digit indicator.
The device allows you to set the min and max limits of the mains voltage, according to which the protection will work out, as well as the delay time (up to 255 sec) for re-enabling the load after the voltage returns to acceptable limits.
Settings are stored in non-volatile memory and do not disappear after power off.
The voltage relay is controlled using two buttons “+” and “-“.
By pressing the “+” button for five seconds, the maximum voltage limit is displayed.
By pressing the “-” button for five seconds, the minimum limit is displayed.
When you press the “+” and “-” buttons simultaneously for five seconds, the delay time for turning on the relay is displayed.
When you press the “+” or “-” button, at the moment the set parameters are displayed, the displayed limit will be changed up or down. If within five seconds no manipulations with the buttons occur, the device switches to the standby mode of monitoring and displaying the current mains voltage.
The analog voltage relay of Chinese production mounted on a DIN rail was taken as a basis.
From the indicated relay, we use a switching relay and a transistor.
AVR microcontroller ATtiny26L is used as a control chip.
Scheme for switching on an indicator with a common cathode.
Setting the relay consists in adjusting the multi-turn resistor R5 until the indicator readings match the readings of the reference measuring instrument.
Scheme :
FUSE;
Source code for a circuit with an OK indicator.
Source code for a circuit with an OA indicator.
Archive of files created in the workflow.
