I am using Arduino Mega 1280 to control temperature in a chamber. The equipments used are as follows.
- Relay board
- 4 no of 24Vdc relays
- 2 no of 220Vac relays
- LCD Display
sensors are inputs and 12V relay board is controlled by arduino. 220V and 24V relays are controlled by 12V relay board.
The problem is when I power the whole system including arduino board, relay board and etc. all the relays switch at once, and off and continue like blinking. This is totally unacceptable according to the program. But when I turn on arduino with usb cable and then power the system, the program works correctly. The system has worked well for several days before this problem occurring.
In the program, I have used Timers and EEPROM. Will these be affected anyhow or will it be another problem? The arduino version I am using is Arduino-0023.
220V and 24V relays are controlled by 12V relay board.
That part is not real clear to me, most relay boards have relays built into the board and their coils operate at the same voltage that the board is rated for, thus a 12V relay board would have built in 12vdc relays. You seem to be saying that the relays on the relay board are wired up to control to external relays, one with a 24V coil (AC or DC?) and one with a 220 volt relay coil?
I guess what I'm saying is that one electrical schematic of your complete setup would be better then a thousand trying to explain the physical system. You might be able to work around the problem symptom with sketch software but it would be better to understand the electrical situation and correct the problem at it root cause.