Power Relay Featherwing Help/Questions

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Kpdcompany
 
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Power Relay Featherwing Help/Questions

Post by Kpdcompany »

Hey guys, My name is Travis Kemp I am new here but not to the community. I own Kemp Prototyping & Design Company in Cincinnati, Ohio and we specialize in end use additive and product development for the Business 2 Business community. We are creating our first product that will use a Feather, Feather TFT, Feather Powerwing High Output Relay. My main concern is we plan to run a heater and a fan, the heater WILL be 120vac and the Fan can be either 120vac or 5vdc. We would like to entertain the possibility of running the heater directly through the relay and possibly the fan too if we can't figure out an easy way to use PWM for the fan then we will, but finding a 5v strong enough has proven difficult so we are considering running a fan and heater together on this relay. My first question, is this basically a solid state relay? Should I be using an ac/dc ssr instead? What would you suggest for controlling a fan with PWM and using PID for the AC Relay? I'm asking about the whole gamut, so if its hardware or software we need please let me know and specify, I am new to this type of programming and am a bit rusty. IF you were in this situation, what would you change or do different? We LOVE suggestions and I will be able to share the project soon enough! Thanks in advance!

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

That is a mechanical relay. For PWM you would want a solid-state relay.

You only mention the voltages of the devices you are controlling. You also need to consider the amperage for sizing the relay.
Also, some types of heating elements are inductive loads, so you would need to derate by 50% or more..

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

adafruit_support_bill wrote:That is a mechanical relay. For PWM you would want a solid-state relay.

You only mention the voltages of the devices you are controlling. You also need to consider the amperage for sizing the relay.
Also, some types of heating elements are inductive loads, so you would need to derate by 50% or more..
Absolutely, my apologies. The heater will be a PTC Style Heater or a Finned Tubular heater, in both cases they are resistive loads thankfully. So far the heaters we have found are around 4-5amps. Obviously I'm not an electrical engineer so I will get any info you need to help me out. Thank you!

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

What is the application? Were you planning to PWM the heating element, or just the fan?

For temperature control applications TPO (Time Proportional Output) is commonly used. It is a type of PWM, but with a much longer time-period. That makes it usable with mechanical relays - and is more efficient for SSR's also due to the reduced switching frequency.

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

adafruit_support_bill wrote:What is the application? Were you planning to PWM the heating element, or just the fan?

For temperature control applications TPO (Time Proportional Output) is commonly used. It is a type of PWM, but with a much longer time-period. That makes it usable with mechanical relays - and is more efficient for SSR's also due to the reduced switching frequency.
Its a proprietary product but its an oven for all intensive purposes. It is sealed, and will be continuously used, most will have it set one of our presets that will keep the chamber at a set temp for annealing/drying is about as much as I can say without NDA :( I am not sure yet honestly I wouldn't mind being able to do both. I was looking into TPO, I'm old school where I was messing with bangbang last time I played with this stuff, haha. So is this "Featherwing Relay" as good as other SSR's for this application?

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

An SSR would still be a better choice than the Feather Wing for longevity. Mechanical relay contact life depends on things like load type, voltage, current & switching frequency. But typical lifetimes are in the range of 10,000 to 10,000,000 operations. Even using TPO with a 5 second period, 1 million cycles is only about 2 months.

For an example of PID temperature control using TPO, see this guide: https://learn.adafruit.com/sous-vide-po ... o/software

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

Fantastic, this is the information I needed, thank you. I will have to go with an SSR, I will not put out a product that only lasts 2 months on a bad day. Do you suggest any specific SSR for this application? Maybe we use the relay for the Fan/Blower since it will not be directly tied to the heater, although I would like to actually set it up so that I can have the heater turn on for 60sec, then have the fan come on. While the heater is inactive with TPO I could still run the fan at a certain % correct? I would like it to have a "standby" fan setting that is lower while the heater is off, then kick back up full blast after the heater is back on and so forth. Will I need anything special to run this SSR and PWM fan control? One of the setups I am looking at is a custom blower/heater combo with a 0-5vdc 3 wire blower. Basically I am trying to also decide on ac/dc for the blower. I have no idea if I could control a regular AC Blower with some sort of PWM, thats beyond my knowledge.

Thanks!

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

Unless space is a primary concern, 'puck' style SSRs are the easiest to work with. You will want one rated for at least 5A @ 120VAC for your heater. And if you are controlling it with a Feather processor, you will want one that will accept a 3.3v control signal. Something in the Crydom CL series should work. Opto-22, Omron and other major SSR manufacturers should have units with similar specs.

A mechanical relay will not give you speed control of your fan. For fan with a brushed DC motor, you can use an SSR rated for DC operation and PWM. Or an N-channel power MOSFET will do the job as well: https://www.adafruit.com/product/355

3 or 4 wire brushless DC fans, a fan-controller chip is the best way to go: https://www.adafruit.com/product/4808

For AC fans, speed control is a little more complicated. An off-the-shelf dimmer module is probably your best bet.

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

adafruit_support_bill wrote:Unless space is a primary concern, 'puck' style SSRs are the easiest to work with. You will want one rated for at least 5A @ 120VAC for your heater. And if you are controlling it with a Feather processor, you will want one that will accept a 3.3v control signal. Something in the Crydom CL series should work. Opto-22, Omron and other major SSR manufacturers should have units with similar specs.

A mechanical relay will not give you speed control of your fan. For fan with a brushed DC motor, you can use an SSR rated for DC operation and PWM. Or an N-channel power MOSFET will do the job as well: https://www.adafruit.com/product/355

3 or 4 wire brushless DC fans, a fan-controller chip is the best way to go: https://www.adafruit.com/product/4808

For AC fans, speed control is a little more complicated. An off-the-shelf dimmer module is probably your best bet.

Thank you so much, I was looking at these SSR's so we are on the same page! I will definitely be going for a brushless 4 wire if possible. I am trying to avoid a 12v PSU as well so hopefully I can find one with 5v that will work well. What is the cheapest way to power a 12v PWM fan when thats the only 12v onboard? Just in case I can't find one 5v.

The 3 wire blower I talked about earlier is a really decent option, BUT would require 24V Power. What are my limitations not going 4 wire? Is PWM still just as reliable on 3wire without a dedicated PWM pin? This part has me a little sideways, hah.

That featherboard looks nice and has temp too which is very nice to have since I am using an SHT30 this seems like the best options for, well, more options, hahah

I very much appreciate your help!

EDIT: I just thought, what is the max ambient temp the SHT30 or any "PCB" sensor can go into? This environment will be no more than 200C but I HAVE to read HIGH ACCURACY Humidity, so thats why I went with the SHT30 initially. Thoughts? Thanks!

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

Well I found this triple power supply, and its a Mean Well so thats good. This will have 5vdc, 12vdc, and 24vdc. This will make it less of a hassle to find a blower/fan that will work and I will just send back the 5v, easy peezy. Then depending on the fan I will get either the board you suggested or below?

I was thinking this for an easy/cheap way to control it? https://www.adafruit.com/product/3190

And this for a more expensive full control? https://www.adafruit.com/product/2927

Mean Well PSU
https://www.amazon.com/gp/product/B005T ... KX15&psc=1

SIDE QUESTION. Can I power the Feather S2 with 5vdc directly through the Battery Plug? I was wanting to keep the port open but I guess it doesn't really matter since I have an SD on the feather TFT? I am mainly referring to providing updates, "profiles" etc. Not sure how that works or if I can do OTA somehow.

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

I was thinking this for an easy/cheap way to control it? https://www.adafruit.com/product/3190

And this for a more expensive full control? https://www.adafruit.com/product/2927
The decision will depend on the power requirements of your fan. The motor wing is good for up to 1.2A @ 12V. The DRV8871 can handle up to 3.6A @ 45V.
Can I power the Feather S2 with 5vdc directly through the Battery Plug?
Probably not a good idea. The datasheet for the charge controller chip does not specify what happens if there is a voltage higher than 4.2v applied to the VBAT pin.

You could supply 5v via the USB pin. Or via a USB plug into the USB jack.

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

Ok got ya, thank you. Its seeming to make more sense now. If I am using the TFT I am able to use it as a "breadboard" style outputs on the TFT correct? I want to make sure I am understanding that stacking correctly. Other than previous mentions, I will have an RGB LED that lights up the inside and be able to program certain colors to certain situations, this is more of something we will work on in the future and will start out making this RGB Led just emit plain white light on an on/off/dimmer UI for the TFT for now it will just be ambient light, but want to make sure its ready for expansion. The other thing is I believe I will use that Power relay to activate our door lock instead, any reason this is a bad idea? Will the life of the relay be adequate for something like that?

Cant tell you how much I appreciate your help, I owe you a few beers if we ever meet!

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Re: Power Relay Featherwing Help/Questions

Post by adafruit_support_bill »

Yes, the TFT Feather Wing can be plugged into a breadboard.

And the Relay should work well for something like a lock since it will not be cycling every few seconds like a heater.

If you are using a solenoid actuated lock, you should wire a flyback/snubber diode in parallel with it to minimize the arcing across the relay contacts.

https://en.wikipedia.org/wiki/Flyback_diode

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

Thank you very much, I appreciate it! I will most likely use a solenoid door lock unless I find a better option. Now only if I can get to programming the board and get esptool to work correctly, see my other thread, but I think this dang thing is bricked, my fault for trusting someone who said they knew what they were doing when instructing me...ya ,not happy haha

viewtopic.php?f=57&t=183721&p=892225#p892225

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Re: Power Relay Featherwing Help/Questions

Post by Kpdcompany »

So that's all sorted, but i hit hurdle. I'm not sure if there is something we can use to design a custom gui with like drag and drop modules etc like hmi's? I bought a feather tft 2.4 but I had plans of some sort of interface similar to the ones you see on Duet3d PanelDues and the like. What's our best option for this? Not necessarily trying to write code from scratch for a TFT Gui haha. Thanks!

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