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Author Topic: Arduino Mega 1280 does not work well when powered at once with whole system  (Read 523 times)
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Hi,

I am using Arduino Mega 1280 to control temperature in a chamber. The equipments used are as follows.
  • Relay board
  • ds18b20
  • 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.

Thank you.
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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.

Sounds like a problem with stable power.  Turning on "everything" at once appears to cause the power voltage to fall too low for the Arduino regulator to keep regulating.  After the initial power spike, things then work.  You may have a defective capacitor (bulk), a connection that is loose or corroded, or simply not a "stout" enough power supply.


Ray
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@Ray, thank you for the answer. I am using 2x12V 5A transformer to power the arduino board, 12Vdc cooling fan, relay board and 4 no of 24Vdc relays. I checked all the wire connections and tightened. This problem is not always happening. What should I do? Should I power arduino board separately and power it first?

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a "stout" enough power supply
Ray, Can you please tell me what is the meaning of this?

Thank you.
« Last Edit: August 29, 2013, 10:28:49 pm by madard » Logged

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I am using 2x12V 5A transformer to power the arduino board, 12Vdc cooling fan, relay board and 4 no of 24Vdc relays. I checked all the wire connections and tightened. This problem is not always happening.

So, you have two power supplies, AC transformers, one feeding the Arduino through a bridge rectifier and the other feeding the relay board and cooling fan through a bridge rectifier and both power units have ample filtering?  The negative side of both power units are tied together to establish a common ground?

I would try playing with the filter caps on the DC side of the full-wave bridge rectifiers.  The relay board should have larger capacitance than the Arduino to give the Arduino time to come up to power and be stable prior to the relays and drivers being enabled.  You also need to ensure that your sketch anticipates the relay board delay in setup() and that output pins are properly pulled up (you should be using high on output as relay is not active - negative logic.)
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Hi,

I am using Arduino Mega 1280 to control temperature in a chamber. The equipments used are as follows.
  • Relay board
  • ds18b20
  • 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.

Thank you.

Quote
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.

Lefty
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I am sorry if my explanation is confusing and these happen because I am not well experienced in using this forum.

I have used capacitors in the rectifying circuit and @Ray, Thank you for your answer and I also think that by modifying setup(), sometimes the problem may be solved.

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220V and 24V relays are controlled by 12V relay board.
What I wanted to say is, coils of the 220V and 24V relays are powered by the relay board.

@Lefty, actually it will be better to post the circuit diagram I will post it soon.

Thank you
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I am sorry if my explanation is confusing and these happen because I am not well experienced in using this forum.

I have used capacitors in the rectifying circuit and @Ray, Thank you for your answer and I also think that by modifying setup(), sometimes the problem may be solved.

Quote
220V and 24V relays are controlled by 12V relay board.
What I wanted to say is, coils of the 220V and 24V relays are powered by the relay board.

@Lefty, actually it will be better to post the circuit diagram I will post it soon.

Thank you

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What I wanted to say is, coils of the 220V and 24V relays are powered by the relay board.

Do you really mean to say that the 12volt relay boards control the coils of the 220V and 24V relays? Where and how the 220V and 24V coil voltage comes from is not defined without a schematic drawing, but those voltage sources are certainly not available on the 12V relay board.

Lefty
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Hi, yes definitely need a circuit diagram, especially showing how you power the arduino from the transformer power supply.
As you say all is well until you power the arduino from the same supply as the relays, also are the relay coils fitted with protection diodes?
Tom.
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