Help - over sourcing mA limits of 462

Discussion of the physical aspects
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jayw
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Help - over sourcing mA limits of 462

Post by jayw »

Asking for some help from those on this forum board who are knowledgeable when working with the BSA462 and it mA MAX limits. I’ve designed a brewing system that is probably over-engineered, but then what else has a Retired Mechanical Engineer got to do with his time.

During my first attempts to use the system, I was not able to open more than 4-5 valves at a time. Usually, this would handle any brewing process. It troubled me that I was probably going over the mA limits of the 462. Not going into how the system was wired, except to say that when I finally found the thread on this forum, titled “Max source power for the BCS462” that I knew I had to rewire the system.

I’ve attached a recent reworked and now
Relay Boards, Power Supply.pdf
(69 KiB) Downloaded 294 times
rewired system using Solid State Relay boards. (http://www.amazon.com/Expansion-High-le ... ge_o01_s00)
to control the 13 motorized valves in the system.

I have an 115/230VAC Regulated Switching Metal Case Power Supply Adaptor Transformer 360W that provided 12VDC – 30A power for the system. (http://www.amazon.com/XKTTSUEERCRR-Univ ... ge_o09_s00) I know way more than I need, but I had it for another project so used it.

Plus, to provide 5VDC power for the BCS462 and the Solid State Relay Boards I’m using an adjustable Step-down (Buck Converter Transformer) (http://www.amazon.com/DROK-Regulator-Nu ... ge_o00_s00) Again probably overkill, but that I believe better than not having enough.

Also, would appreciate a look at the Auto-Off-On switch wiring drawing included, is it correct?

I’ve not applied power to the system since I’m not sure I the rewiring I did will not smoke the system. I would appreciate any comments or advice.

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Joe
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Re: Help - over sourcing mA limits of 462

Post by JonW »

Your basic approach looks fine. The On-Off-Auto looks good too. Doing the switching on the low voltage side like you did is my preferred way as well.
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Re: Help - over sourcing mA limits of 462

Post by jayw »

Thank you, Jon for taking a look at the drawing.

I'll plug it in this evening and see if I solved the problems I was having.
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Re: Help - over sourcing mA limits of 462

Post by JonW »

I think one of the confusing things with outputs is that many people have never experienced what "current draw" really means. The assumption is that if it is a 5V output, then you can put a 5V relay or other 5V device and power it from the output. In some cases, this can work, if the device or relay only needs minimal current to power it. We usually try to use the term "trigger" when talking about using the outputs. The output can trigger a device - not power it.

jayw - when you get a chance, please post up some pics of your system. I'd love to see what you've done.
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Re: Help - over sourcing mA limits of 462

Post by jayw »

JonW,

Thanks for the assistance, yes I will post photos of the system after I get everything tested.

I have another problem, after finishing the wiring per the drawing in my previous post, the LED's will lite when the relay for the valve is activated. However, when the valve is deactivated the LED stays lite.

I tried to place different size resistors in the circuit, which did not solve this problem. The only way to get the LED's to turn off is by cutting the 12vdc with a switch I wired into the circuit from the power supply.

Have any ideas what the problem may be?
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Re: Help - over sourcing mA limits of 462

Post by JonW »

It's likely happening because of leaky SSR's (they all do it). Depending on the current draw of the valve, you may be able to put the LED in series instead of parallel. This is not my area of expertise, but I think the combined "turn on" current of the two should be enough to keep the LED off.
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Re: Help - over sourcing mA limits of 462

Post by jayw »

I will make the changes and let you know.

Thanks
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Re: Help - over sourcing mA limits of 462

Post by jayw »

Rewired one valve and LED circuit to a series circuit. Did not change how the LED reacted. Still stays lite after relay deactivated. The only change is LED not as bright, which can is with the added resistance of the wiring and valve.

I guess I just forget about the LED's on the panel, just disconnect then. Will need to leave them on the control enclosure. Otherwise, it will have a bunch of holes in it, not good for a wet environment.
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Re: Help - over sourcing mA limits of 462

Post by JonW »

Mechanical relays would solve the problem. Unfortunately, SSR's leak current. Hopefully someone else will have a solution to be able to utilize the LED's wired via the SSR's.
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Re: Help - over sourcing mA limits of 462

Post by oakbarn »

I have some 110 vac LEDs that I use when I want to "know" that something is powered. They fit into a normal light bulb socket so they are not the small Panel LEDs but I do not have to worry about leakage. I also have 12 vdc LEDs on my DIN Physical switches (DPST or DPDT) Toggles. You do not need them for "One Shot" as that is so fast you will never see the LED, but for a "switch" that is "On", the LED helps.
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