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Topic: Seeking an I2C 8-16 channel relay board (Read 1 time) previous topic - next topic

CRC_failure

That seller would never see my money... but that's just me. Here's a similar model from a more reputable seller. Reasonable shipping too, especially with a 10pc order.

https://www.ebay.com/itm/PCF8574-IO-Expansion-Board-I-O-Expander-I2C-Bus-Development-board/351875821618?hash=item51ed6ef032:m:mRxQbdJsdU7r1HQPlvNq_QA
Hopefully they will stack like railroad cars as we may have 8 of them. (Or eventually 16)
Wish vendors would include dimensions.

Lacking any clips that {unknown} width may have to make a /_________\ slot in a bar of some plastic to slide them in from the end; then DIN-clip the bar to the rails.

CRC_failure

As usual, the "Better, Cheaper, Faster; choose any two" rule applies...

On relay output boards, I can find 8-port relay boards. Great.

But I want ones with header pin so I can just plug a IDC cable in.
There are a few like that:
https://www.ebay.com/itm/322834065204for example.

But I want 24VDC relays, not 5/12V. They exist, but it appears only with screw terminals.
And I want DIN rail mounting, but.....

And it's unclear if the various units have or lack LED's on each relay channel.

Gnash....




avr_fred

Once and done project or on-going? How many total boards do you need?

CrossRoads

You can populate my board with 5A, 24V coil SPST relays
https://www.digikey.com/product-detail/en/omron-electronics-inc-emc-div/G5NB-1A-E-DC24/Z2773-ND/1731473

The TPIC6C595 shift register that sinks the coil current can handle that no problem, it's rated to 33V.
I've designed in an LED indicator per channel, and can customize the board size if you can define what it is you want. Right now it's 50x80mm.


If you want IDC, I can even add that too, altho that usually implies 2x3 or 2x5 or 2x8 or whatever length header and smaller 28 gage 0.05" spaced ribbon cable.  What kind of currents are you switching?

http://www.king-cart.com/phoenixent/category=RECEPTACLES-SOCKETS+IDC+.1SP+%2526+2MM+SP
http://www.king-cart.com/phoenixent/category=WIRE+%2526+CABLE+-+BULK


Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

CRC_failure

Not one-off, we're building them into a product, but it's low volume.  
This unit will require 4, future units more or fewer.

(BTW, another gripe about the descriptions is it's not always clear if the control lines are active low or active high. I was excited about http://www.dx.com/p/arduino-compatible-8-channel-24v-relay-module-expansion-board-145731 but that's not clear, and of course, it's out of stock.)

CRC_failure

#20
Oct 29, 2017, 05:21 pm Last Edit: Oct 29, 2017, 05:34 pm by CRC_failure
We alas need SPDT.

I want an IDC on the input to meet the cable from the I2C decoder.

The output will be cables headed out of the cabinet.

& found https://www.aliexpress.com/item/5pcs-relay-24V-8channle-relay-module-relay-expansion-board-low-level-triggered-for-arduino/32522339358.html but check the shipping for Q4.

avr_fred

I would expect that board (dx.com) is active high as there are no optocouplers, only a single transistor (or fet) per coil.

I would be very cautious with using the typical Chinese relay boards on a commercial product, personally, I would never do that. The majority of the boards out there do not meet basic US safety standards for minimum creepage and clearance distances to prevent flash-over on both the lv and hv sides of the relays. There are a few boards with good quality relays and correct board layout/routing but they are the exceptions, not the rule.

Feel free to prototype with them but put them into field, especially into a big citiy where inspectors look for a UL label on everything, never.

CRC_failure

This product is all Class II; there's no line voltage within. The relays we're talking about shall drive only 24vac, and no inspector has even looked twice so far.

Yea, lots of variable quality on Pacific Rim stuff; but some of it is OK.



Batman_429

here is an i2c relay board
16 ch I2C relay board from ncd.io
it has i2c in out so you can daisy chain them.
You can connect upto 8 of these board with one arduino, if you ever need to connect more you can use i2c mux.
On the same website you can find all kinds of i2c shields for arduino.
Its all plug and play, so no need of any soldering.

Thanks


CRC_failure

here is an i2c relay board.....
I looked at the ncd models but the end cost added up to be far higher than the other approaches I've seen to date.


Batman_429

They are higher then ebay ones but again if you add up the cost of good relays, phoenix connectors, switching power supplies and build quality. A cheap relay board could work for few weeks but if you want something which you want to use for days and days it will be better to go with industrial grade ones.

CRC_failure

That seller would never see my money... but that's just me. Here's a similar model from a more reputable seller. Reasonable shipping too, especially with a 10pc order.
Sigh, only the one source I cited has decoder boards with mounting holes. Everyone else is holefree and will require more effort to mount.

CRC_failure

They are higher then ebay ones but again if you add up the cost of good relays, phoenix connectors, switching power supplies and build quality. A cheap relay board could work for few weeks but if you want something which you want to use for days and days it will be better to go with industrial grade ones.
That's why I've been buying samples from several sources before jumping in the deep end.

CRC_failure

So I just got some of my 24V 8 channel boards in. They look very nice.

I also got my order of PCF8574-IO-Expansion-Board in. They are tiny. . And thus hard to mount.

I'm puzzled by them bringing out an INT pin with the 8 outputs; as least that's what it seems to be. But INT is on the I2C side of the chip, not the parallel, correct?



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