TTL Output Relay Board Help

[cwb212001]

Greetings,

I'm new at this and I appreciate any help you can offer.  I was having a hard time finding solid state relays with both NO & NC contacts and thought my problems were solved when I found these simple kits with conventional relays that could be activated by the WebControl TTL outputs.  It runs on its own 12vdc power source.  The description says that it has "easy one wire drive, high is on, low is off".  If you look at the relay board, there is 3 inputs: 12vdc in, ground & 'in' for activation.  Am I correct in thinking I need a ground reference for the 5vdc high from WebControl; I can't just run one wire from the WebControl output to the input of this relay board?  So, to give it a ground reference I would need to tie the WebControl's ouput ground (pin 9 or 10) to the ground of the relay board which is common with the relay board's power supply.  The kit supplier said this would work just fine.  Anyone see a problem with this?  Thanks again for any suggestions.
 
P.S. Forum rules won't let me post a link to the relay board or even a picture of it so if you want to take a look at what I have and what I am talking about please search on ebay for ...
 

K004 KIT - relay board simple to use 12v operation supports logic level also
ebay item number 321081645916
 
Forum admin,
 
Not trying to sell anything... this is the only way I know how to let the readers see what I have.  Thanks!

 

[BraveSirRobbin]

Well, we gotta watch the spam from first time posters here, but HERE is the link.   I don't see any problem with just referencing a ground from the digital outputs, as long as they can drive 3.3mA you should be fine and that they don't exceed the voltage logic level of that device (though be aware that I don't own a WebControl unit).   I'm guessing that board is just using the base of the transistor to trigger the relay's coil.
 
BTW, welcome to CocoonTech!

 

[rossw]

 thought my problems were solved when I found these simple kits with conventional relays that could be activated by the WebControl TTL outputs.  It runs on its own 12vdc power source.  The description says that it has "easy one wire drive, high is on, low is off".  If you look at the relay board, there is 3 inputs: 12vdc in, ground & 'in' for activation.  Am I correct in thinking I need a ground reference for the 5vdc high from WebControl; I can't just run one wire from the WebControl output to the input of this relay board?  So, to give it a ground reference I would need to tie the WebControl's ouput ground (pin 9 or 10) to the ground of the relay board which is common with the relay board's power supply.

 
You got it exactly right.
What I've done here BTW, is to run a 12V supply to the WC board.
The same 12V that feeds the WC board connects to the relay boards 0V/12V inputs.
The TTL outputs from WC then go to the relay driver boards inputs.
 
You have done well to choose the "active high" version in my opinion too.
There are two kinds, and it's almost impossible to tell them from the ebay ads. One is active-high, one is active-low.
 
I use the 4 and 8 channel relay boards and have never had one fail.

 

[apostolakisl]

Yes, I agree.
 
Also, it looks like the version pictured is a 5v version.  The description at times talks about 12v and other times 5v. Just be sure which one you want and that you get it.  

 

[cwb212001]

Thanks for all of the help!  It looks like I'm good to go.

 

What I've done here BTW, is to run a 12V supply to the WC board

 
 I do have a regulated 12vdc (as well as a regulated 9vdc) supply but I was worried about overheating like it warns of in the manual as it is going to be in an enclosure.  Does it seem to stay cool enough at 12vdc?
 

 The description at times talks about 12v and other times 5v.

 
The item description was very confusing and the stock picture used only added to it.  It took three emails to figure out I was getting the 12vdc version and I still don't think they understood why their description wasn't clear.
 
Now that I've got this part figured out I'll get the code loaded and try everything out.  I think I'm pretty good there but I know where to go if I run into any problems.  Thanks again!
 

 

[BraveSirRobbin]

I guess I'm wondering why the need for a 12 volt powered source.  Does the WebControl only provide this output?  Are you powering it from an already existing 12 volt source?  Is what you are switching require a 12 volt high current switch via the relays contacts?

 

[cwb212001]

The WebControl's manual recommends using 9VDC for it's power source but says you can use 12VDC as long as it doesn't go any higher than that because it's regulator might overheat without a heatsink.  I think what rossw was referring to was he powers his webcontrol with 12VDC and also uses the same supply for his relay boards and it sounds like it works fine for him  The relay kit's I have require 12VDC, thus the extra power supply if I choose to run the 9VDC regulated adapter to the WebControl.  I think I'm being overly cautious here.  The WebControl's outputs are 5V/0V TTL logic level.  I chose to use these relay board kits because I wasn't finding any SSRs with both NO & NC contacts.  But, now that I think about it, I probably could have used SSRs and just inverted my logic for NC.  I do have a higher current device but SSRs probably would have worked. Oh well, I've got the boards so I'll use them.  Thanks again

 

[BraveSirRobbin]

Yea, I guess that was my initial question's meaning.  What are you switching that requires relays in the first place and why does it dictate that 12 volt operation.