Feedback on relay how-to document

[Nofossil]

Once again I'd like to tap into the collective wisdom of the forum.

Over the years with the NoFossil Control System (NFCS), I've found that a lot of folks who are pretty handy with plumbing and electrical wiring get a little intimidated by relays. As we roll out our Vesta product line, I want to maintain the original mission of providing helpful information on our web site, and this seems like an area that's worth looking at.

I've written a mini-tutorial on relays and I'd appreciate any feedback. It's intended to be helpful for folks who've purchased on of our systems, but it's also intended to be a resource for anyone looking at incorporating relays into a system. Please ignore any Vesta-specific content - I'm really more interested in how well it explains relays in general.

I'm hoping that the text and illustrations are clear and informative. Is the level of detail about right? Are there common questions that I didn't answer? Are there other great resources that I should link to?

Here's (broken link removed to http://www.vecs.org/relays.php) and a teaser picture. Thanks....

(broken image removed)

 

[kopeck]

That's awesome, great write up!

For those of us that work with technology relays effectively give you logic to control where you want power.

They kind of look intimidating, but once you get a handle on them they will open up a whole new world.

K

 

[ewdudley]

Yikes.

 

[Nofossil]

Yikes.

Is that a good 'yikes' or a bad 'yikes'? I wrote this because a lot of folks have that general reaction when looking at relays. I'm hoping this provides some level of de-yikeification. Should I add a bit more detail and/or go more slowly? More examples?

 

[__dan]

It's very nicely presented and clear. It shows a good effort to provide support.

I would make two comments: The installer will just be looking for a marked terminal strip to land wires. markings would be like, boiler 1 circ, boiler 2 circ, OA reset injection circ or valve, OA sensor, HWS sensor, boiler return sensor, zone circ, DHW circ, zone valves, tsat call for heat, DHW call for heat stat, at the abstraction layer. The installer would never normally get involved with NO, NC contacts (the hardware layer), unless he was custom building his logic own solution. I'm assuming you would be doing the custom logic, operating sequence programming.

Sometimes the terminal strip is plug on pins. In that case you could provide marked leads whips, circ X, sensor Y.

The variable speed blower failsafe, normally you can never disconnect the motor from the VSD output when the motor is powered or spinning. Any disconnect would be marked "do not open under load". There is an inductive kick when opening under load that will damage the drive output. Drives are powered down at the input. If you were to switch from the boiler VSD to the VS 1108 VSD, you would have to power down the boiler blower control at the input, wait for the motor to spin down, swap the blower motor from the boiler to the VS 1108, then power up the VS 1108. Switching back would be the reverse, power down the VSD input, wait, swap the load at the output, power up the alternate VSD.

 

[Nofossil]

Thanks, Dan. This is a general-purpose controller so each installation will likely use the relays for different purposes. Can't really label things unless we start making semi-dedicated versions.

Excellent point on switching VS controllers. In our system you could have a rule that turns off the VS control, waits for a while, then switches. The user would have to be aware of what the other controller is doing. I'll add a comment / warning. The tutorial is about relays, but it's important not to suggest incomplete solutions.

 

[__dan]

The controller for wood gasification boilers with storage, essentially you have three sources: wood boiler, backup boiler, storage, one or two mixing or reset scenarios: boiler return mixing, OA reset mixing, the load circs or valves, a variety of sensors, that's pretty complex to automate the sequence of operation.

It's imo beyond the capacity of first time users and installers. Most of the wood burners have some type of manual control changeover, and have trouble controlling the storage circs for maximum efficiency.

That's the application I was assuming you were targeting. The user would come to you either with a plumbing, equipment arrangement, or look to you for one of the standardized layouts, then each controller would be custom built, programmed, inputs outputs labeled, for each dedicated application based on the user's particular equipment package. Your experience would move the project along the right track, keep it on target, and avoid costly design or implementation errors.

It is beyond the average residential wood burner to implement their own control sequence of operation using a programmable controller. They would have to be a control pro. They would be looking for a custom built and engineered control solution, using your expertise to prefabricate a customized solution. Something they can just read the labels and land the wires.

 

[STIHLY DAN]

That is a good pic, I would also add a pic of nc and no in 1 relay. And to change the subject, I saw you sold a control in some post that I cant find Again. Whats the name of your co. So I can e-mail you.

 

[Nofossil]

..... that's pretty complex to automate the sequence of operation...... It is beyond the average residential wood burner to implement their own control sequence of operation using a programmable controller.

Agreed. It took me a long time to figure it all out, and I'm still refining it. Safe to say that the folks who have bought (or built) these controllers are well above average ;-)

We are in discussions with a couple of manufacturers about adding our controller as a preconfigured option for complex installations. If that happens it will be exactly along the lines that you suggest. In the meantime, we have folks looking at using them for a whole host of monitoring / control / datalogging applications that have nothing to do with heating. I'm pretty excited about one that's going into a custom malt operation, and there's another in a brewery. Most of our customers tend to be highly motivated, willing to learn, and doing something pretty original. I'm just trying to anticipate the stumbling blocks. Thanks for your comments.

 

[Clarkbug]

Nofossil, I think your write-up and graphics were very helpful. Excellent, and easy for a non-electrical guy (me) to understand. I think this is a great resource.

 

[Nofossil]

I've lost track of who the moderators are these days, but I'd be happy to make a non-Vesta version of this as a resource for hearth.com if there's a general sense that it would be helpful. In the meantime, any other feedback?

 

[arbutus]

Good write up.

If you were making a generic tutorial I would keep your illustrations but also add photos and documentation showing a real life example.
Understanding the theory is great, but showing the whole sequence starting with a relay inside the white box as purchased from the supply house, an enclosure, mounting suggestions, and making the final product look professional really helps too. A link to a youtube video works too.
Dan's suggestion for labeled termination points or color specific leads for your controller is excellent as well.

 

[jebatty]

Relays are super cool, and they can enable so many cool things. I like your descriptions and prefer the schematic/theory approach because it lets a user be creative in putting relays to work. I think the coolest thing I have done, and an observer doesn't know a relay is involved, is the relay-controlled linear actuator on my slider shop window. When the boiler is switched "on," a DPDT relay energizes the 12-24vdc actuator +/- in one direction and it opens the window 6" to provide combustion air. When the boiler controller shuts the boiler down at end of burn, the DPDT relay energizes the actuator -/+ in the other direction and it closes the window. The movement of the window really grabs the attention of people who view my system.

Keep up the good work.

 

[huffdawg]

As someone who is purchasing a Vesta controller I have been doing a lot of self study on the www.vecs.org site. All of the how-to and the demo application sections are excellent for control newbs like me, its been a great help.. the schematics are like a picture ( worth a 1000 words) , The rule programming should be a good challenge also. I have a close friend who is a software engineer who says after having looked at your manual on rule programming that we should be able to get it done without too much trouble

Huff

 

[smwilliamson]

As someone who is purchasing a Vesta controller I have been doing a lot of self study on the www.vecs.org site. All of the how-to and the demo application sections are excellent for control newbs like me, its been a great help.. the schematics are like a picture ( worth a 1000 words) , The rule programming should be a good challenge also. I have a close friend who is a software engineer who says after having looked at your manual on rule programming that we should be able to get it done without too much trouble

Huff

Agree great write up