Looking for 16channel relay board that works with BCS

[mliptack]

What relay boards are others using?

I will be using the board to trigger valves and pumps - looking for 12 - 16 channels.

Found this one on Deals Extreme: http://www.dx.com/p/16-channel-5v-relay ... .VKDgHAVCs but would prefer a slightly smaller footprint if possible.

Cheers!
Max

[JonW]

Several of us use the ones from Electronics Salon on Ebay.
http://stores.ebay.com/Electronics-Salo ... =349055719

Note that you can use a 12V or 24V relay board. The voltage is usually described as the coil voltage of the actual relays. You use a separate power supply to power the relays on the BCS 5V is merely an input trigger to the relays.

Also note that some relay boards can be triggered by either a ground trigger or a 5V trigger and are only untriggered when there is no power or ground provided on the input. These boards will not work with the BCS as the BCS pulls the output to ground when not active and sets it at 5V when it is active. In both cases, those other relay boards will be triggered which makes them unusable.

[mliptack]

Hey Jon - Thanks for the reply, you're probably getting sick of all my questions. But I appreciate your help.

Yesterday a bit of my time trying to get the relay board that I have working with the BCS. Perhaps some pictures would help. This relay was originally purchased with the Brewtroller platform - I was hoping to be able to use it (already had it mounted in the panel & its very compact).

I tried suppling 12v separately to the PWRIN terminals. But I guess I am not quite sure where the 5v trigger should go. I tried the GND on Pin1 of the Comb and an out on the BCS - with no results.

Let me know what you think based on the pictures below.

Thanks!
Max

[mliptack]

Last picture of terminals down the center row.

[JonW]

I tried suppling 12v separately to the PWRIN terminals. But I guess I am not quite sure where the 5v trigger should go. I tried the GND on Pin1 of the Comb and an out on the BCS - with no results.

Let me know what you think based on the pictures below.

You really need to stop experimenting as you can blow one of the outputs on the BCS if you don't know what you're doing with it.

Without the specs for the relay board, it's hard for me to give you an accurate answer as to whether you can use it. However, from the looks of it, I don't see any darlingtons on the board, so I don't think it can be driven with 5v.

Let me try to explain the darlingtons so you know how the 5V trigger works. Let's say you have a 12V powered relay. You know that applying 12V to it will cause it to switch. On the switched terminals (input/output) of that relay, you can wire in a high voltage device like a 110V pump. The end result is that you can turn a 110V pump on and off by energizing the relay with 12V to it. Most microprocessor based devices only output either 3.3V or 5V. In the case of the BCS, it outputs 5V. We can't power the 12V relay from the BCS because the BCS only outputs 5V with 20mA of current, but the relay needs 12V at probably 50mA or more of current.

So now the question is, how do we get the 5V output to turn on a 12V relay? That's the job of a darlington transistor (or opto-coupled relay). The darlington is a circuit chip that is really just a very small relay. Like our previous 12v/110v example, the darlington can have 12V on its switched terminals (input/output) and when powered (triggered) by 5V, it will switch its output. So now, we have the BCS output the 5V needed to power the darlington, which then the darlington outputs 12V to power the relay, which then outputs 110V to power the pump. This sounds like a like of step-ups in the loop, but this is how microprocessor based systems work (not just the BCS).

This brings us back to the relay board. You need a board that has a separate power input for powering the relays and a low-level input (5v) for triggering them. In my case, I was using 12V liquid valves, so I decided on using 12V powered relays. This way I only had one additional power supply in my system. If you are using 24V valves, I would suggest using a 24V relay board just to keep it simple.

[mliptack]

Jon - I will use a 5v supply instead of the BCS in lieu of your warning. I appreciate the detail in your post.

I ordered the dealsExtreme board and also an 8ch board from Amazon (I have had to many bad experiences with eBay & PayPal - I prefer to stay away from them whenever possible). I will give both of these a test drive and report back my results for anyone else who is looking for a suitable alternative.

[mliptack]

Update:

So I got the 16ch Relay board that I ordered from DX.

After a few trials, I was able to successfully pair it with my BCS-462.

Best of all, it uses 5v so I can eliminate the 12v supply that I have in my panel.

If you plan on using one of these relay boards, Connect 5v+ to VCC; V- from the 5v supply to the GND and jump the GND to the Ref A & B terminals. Then connect your outputs to the IN1-IN16 terminals.

Nice and easy to use - and a fraction of the price of the alternatives! Less than $25 shipped!

Cheers!
Max

[mliptack]

The only con that I am seeing now is the footprint. This Relay board could have been squeezed into a smaller size. Still not bad for what it is, I bought a 12v 8ch relay board from amazon that is a little over 1/2 the size so it was smaller than my backup plan.

Dimensions: 5.94 in x 3.82 in x 0.59 in (15.1 cm x 9.7 cm x 1.5 cm)

[JonW]

STOP!!! GO BACK AND READ EVERYTHING I SAID ABOUT POWERING RELAYS and TRIGGERING RELAYS!

You are going to blow your BCS if you keep doing what you are doing.

Just because you were successful in making the relay work does not mean that the way you have it wired up is the correct way.

You need to use a separate power supply to supply the power to VCC on the relay board. DO NOT USE THE BCS!

I zoomed in the picture from your link on the 5VDC relay board and the relay's are marked SRD-05VDC-SL-C. A quick google search gives me the specs on that relay (http://microcontrollershop.com/product_ ... ts_id=5919). Each relay coil consumes 85mA of current. The BCS is designed to ouput 20 mA as a TRIGGER - NOT TO POWER THE RELAY!

[clearwaterbrewer]

^^^ pin that post.... this is why we can't have lawn darts, cap guns, or cherry bombs......