Arduino Forum

Using Arduino => General Electronics => Topic started by: bsanchezgt on Dec 10, 2018, 01:03 am

Title: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: bsanchezgt on Dec 10, 2018, 01:03 am
Using a Velleman VMA436 8-Channel Relay Board and an Arduino Uno R3 along with an Adafruit Audio FX board. Trying to synchronize music to 110VAC lights. I am seeing some strange behavior that is related to load on the output side of the relays. I have the relay outputs wired to standard 110V power outlets. When I have nothing plugged into the outlets, the system works perfectly. When low load 110V lights are connected, it functions mostly without issues. However, when I plug in light fixtures that have a brick transformer light fixture on it to the outlets, it interrupts the arduino script and does not function at all. I know each relay is not even coming close to the 10A limit they have.

I feel like I am seeing effects of the opto and coil side of the relays both being powered by the arduino. Bouncing back at the arduino and causing it to reboot, etc. The relay board has 12 pins in the following order: VCC, GND, IN1-8, COM, GND. The COM & GND after the IN channels come with a jumper on them. I have tried pulling off the jumper and powering the relay board across the VCC + GND with a 9VDC battery and connecting my arduino ground to the COM and inputs on the relay boards to the corresponding Digital Outputs of the arduino. This gave me consistent functionality as long as I did not use the light fixtures that have a brick transformer plug.

Any other suggestions to further isolate the arduino from bouncing and feedback from the relay board? I am also powering the audio fx board from the arduino power. Perhaps I am also putting too much load on the available power of the arduino and causing a reset on the arduino as well?
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: JohnRob on Dec 10, 2018, 04:07 am
"Bricks" don't take kindly to being switched ON and OFF.  Each time you switch it a large spike is generated.  Depending on the "brick" design it could be on turn on or turn off.
The spike can be such that it travels through the air or some ground etc.  Can't tell more without a schematic and layout.

Perhaps it would be easy to move the relay from the primary of the brick to the secondary, and not having to switch it on every actuation.


Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: Paul__B on Dec 10, 2018, 04:14 am
Your question is a trifle confused.  You refer to "the available power of the Arduino".  The Arduino has no "available power" - what are you actually using to provide 5 V power to the Arduino and the relay board?

Unfortunately, I cannot find a circuit schematic for that particular board!
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: sterretje on Dec 10, 2018, 08:04 am
Unfortunately, I cannot find a circuit schematic for that particular board!
https://www.velleman.eu/downloads/29/infosheets/vma436_scheme.pdf (https://www.velleman.eu/downloads/29/infosheets/vma436_scheme.pdf)
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: Wawa on Dec 10, 2018, 08:11 am
Unfortunately the circuitboard doesn't match that schematic diagram.
Leo..
Title: Reputational disaster for Velleman!
Post by: Paul__B on Dec 10, 2018, 11:28 am
Unfortunately the circuitboard doesn't match that schematic diagram.
Sorry to be obtuse, but that is precisely what I implied when I stated "Unfortunately, I cannot find a circuit schematic for that particular board!".

The Velleman VMA436 product page (https://www.velleman.eu/products/view/?id=439228) erroneously links to that schematic (https://www.velleman.eu/downloads/29/infosheets/vma436_scheme.pdf) which is a nice diagram for the common eBay 8-channel relay boards with the "JD-VCC" jumper
but

bears no relationship to the Velleman VMA436 board pictured on their website and described by the OP.  And my reasonable searches fail to locate the correct diagram to explain why the board links the common to ground.  Presumably it simply means that the common is indeed the cathodes of the opto-couplers.

This is a truly shocking indictment on what is considered to be a quality German Belgian kit supplier.  Poirot would be appalled!
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: AWOL on Dec 10, 2018, 11:35 am
Velleman are Belgian, aren't they?

@Paul__B is there any good reason you change the topic title in your responses?
Title: Making headings useful
Post by: Paul__B on Dec 10, 2018, 11:46 am
@Paul__B is there any good reason you change the topic title in your responses?
Yes, as previously explained, to function as a descriptive, meaningful subject title and summary for my responses.

(Rather than mindless and useless repetition which on that expectation does not even appear on some or many forums.  :smiley-lol:  )
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: AWOL on Dec 10, 2018, 11:50 am
Would you mind awfully refraining from changing the topic title in your responses?

Thank you.

Yes, as previously explained, to function as a descriptive, meaningful subject title and summary for my responses.

(Rather than mindless and useless repetition which on that expectation does not even appear on some or many forums.  :smiley-lol:  )
So, it's all about you?
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: Paul__B on Dec 10, 2018, 11:51 am
Would you mind awfully refraining from changing the topic title in your responses?
See above.
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: AWOL on Dec 10, 2018, 11:56 am
Problem is, in the summary, they look like new topics.

Please don't.
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: sterretje on Dec 10, 2018, 12:40 pm
Unfortunately the circuitboard doesn't match that schematic diagram.
Leo..
Apologies to everybody.
Title: Re: 8-Channel Relay Board Causing Strange Behavior with Arduino Uno R3
Post by: bsanchezgt on Dec 10, 2018, 01:59 pm
@JohnRob I have resolved to not including the "brick" powered devices in this application for now at least.

@Paul__B the Velleman product page has been less than useful. When I refer to the Arduino power, I am referring to the 5V pin on the board. This is actually how I found Velleman suggested wiring their relay boards for the 4-channel equivalent of this board here: https://forum.vellemanprojects.eu/uploads/default/optimized/2X/e/e4191a9c00c539ce54809b3ab8701fa2aefed8d5_1_690x229.jpg

They also allude to a JD-VCC pin separate from the VCC which is non-existant on the 8-channel board. From testing, it does seem that removing the jumper and connecting the arduino 0V to the COM pin of the relay board does complete the coil side of the board circuit and then just powering the VCC & GND pins of the relay board with a separate 9V battery is effective.

But, I still see the same issue when the "brick" style powered devices are used. If it were truly isolated, wouldn't it be able to function regardless of load on the relay output?