Relay Board for 24VDC Solenoids

[Nick0341]

Long time listener, First time caller.

Alright folks, I'm in a real pinch here. I am set to do my inaugural brew in two days and using the BCS460 to control my solenoids on my glycol header going to my ferms. I've spent entirely too long working on this with no results. Here is what I have:

BCS460
(3) 24VDC solenoid valves controlling the header supply to tanks.
UNO POWER 24V power supply
5VDC power supply (cell phone charger)
Sainsmart 8 channel relay module

I have a sainsmart 8 channel relay board that has 5VDC coils. I have tried powering with a 5VDC power supply to the board and then then connecting the pins to the BCS OUT and no luck. In an effort not to bog down the forums, I've been searching but no luck. I think I may just have the wrong relay module.

I've looked around and there is just too many options out there. Can someone give me a clue on which relay module to get?

I was looking at this:
http://www.amazon.com/ELECTRONICS-SALON ... 228%2F5V-1

Any expedient help would be greatly appreciated. We are opening our doors in 3 weeks and I'm in panic mode.

Thanks

[JonW]

Yes, the Electronics Salon boards will work fine and are what I suggest people get.

Any particular reason you are using 5V relay boards? Since you are already using 24VDC valves and have a 24VDC power supply, I would get the 24VDC relay board to match.

If you were getting the 5V relays because the BCS puts out 5V on the outputs, then you REALLY need to read this thread: http://forum.embeddedcc.com/viewtopic.php?f=17&t=2587

Bottom line - the BCS does not power the relays - it only triggers them.

[Nick0341]

Jon

Thanks for the reply. Can you confirm that this one will work?

http://www.amazon.com/ELECTRONICS-SALON ... +8+channel

[JonW]

Yes, that will work just fine.

[Nick0341]

Thanks Jon

I really appreciate you very quick response!

[Jowler]

One of the problems I encountered is that the BCS is a sourcing device (5V high signal=triggered) and most inexpensive relay cards are looking for a sinking device (0V signal or ground path = triggered). I ended using a 12V 16 relay card that was triggered by a source. It is easy to think of thing as a sinking (ground path) or sourcing (+5V signal)

[Nick0341]

I got the new 24V relay board in. I've wired the 24V power supply to the VCC and grounded both grounds to the system. I wired the solenoids to normal open. I've wired Out0 to the IN screw terminals on on the board. I cannot get the BCS to control the relay. I'm not sure it's sending a signal. Also the LED lights on the relay board do not turn on.

I did wire the solenoids to normal close in the beginning and the solenoid fired. I can turn the BCS on, it communicates with my PC and the temp probes work so I have to think the BCS is good.

Any ideas or help would be greatly appreciated.

Thanks
Nick

[JonW]

As a test, you can use the 5V out on the BCS to connect to one of the IN terminals on the relay board and it should trigger it (just like when one of the outputs is turned on).

Also, you said you connected both grounds to the "system" - I'm unclear what you mean by this. Do you have a ground from the 24V PS going to the relay board and also a ground from the BCS going to the relay board? All grounds need to be connected together.

Also, just a final item to ask about... is the power supply 24VDC and not 24VAC?

[Nick0341]

I hooked up the +5VDC outlet on the BCS to one of the IN ports and nothing triggered and the led did not light up.

On the two grounds, there are two GND screw terminals on the relay board next to the VCC. I wired both of those to the ground on the system. By the way, the ground on the system is wired back to the power plug coming in.

The PS is definitely 24VDC.

Thanks

[JonW]

I'm still unclear as to what you mean by "the system". Do you mean your control panel?

The two Gnd terminals on the relay are common terminals, so you don't need both of them wired to earth ground. You do need the earth ground, bcs ground and the 24VDC ground all tied together. I believe this may be where your problem lies.

VCC on relay board to 24VDC positive.
GND on relay board to 24VDC ground.
GND on relay board to BCS ground.
IN-1 on relay board to a BCS output (or 5V+ for testing)
GND on BCS tied to earth ground.