Absolute cheapest way to do simple logic on many points

[rjk_cmh]

I have an application that needs 20 inputs and 20 outputs with only 10 XNOR and 10 NAND blocks. I could do it with relays, but this could end up costing more than some PLC options. On the other hand, a PLC might be kind of overkill. What is the absolute cheapest way to do this, do you think? Keeping in mind that it requires standard industrial 24v I/O.

I whipped up the logic in some software that I already had and have attached it to this post, but that won't be the hardware I use because it is wildly expensive.
View attachment Status lights.pdf

 

[alan_505]

Maybe a Click PLC with an input and a output card.
Free software and hardware is not very costly.

 

[rjk_cmh]

Maybe a Click PLC with an input and a output card.
Free software and hardware is not very costly.

I looked at the Clicks since I have used them before, but a lot of stuff is out of stock. It turned out that it would be cheaper and in-stock to use P1000 modules with the $66 Arduino controller, but I'm not super comfortable with that environment either.

What I would love to see is tiny logic modules that are in the same form factor as ice cube relays, but maybe have like 2-3 inputs and 2-3 outputs with extremely basic logic that could be programmed in.

 

[Ken Roach]

Some of Turck's multiprotocol I/O blocks have a simple "Field Logic Controller" engine built into them.

Back in the day I did little stuff like this with CompactBlock I/O and the A-B DeviceLogix engine, but that was in the heyday of doing distributed control on DeviceNet.

Never underestimate the eagerness of a customer to discard their backup configuration files and documentation.

 

[rjk_cmh]

Some of Turck's multiprotocol I/O blocks have a simple "Field Logic Controller" engine built into them.

Back in the day I did little stuff like this with CompactBlock I/O and the A-B DeviceLogix engine, but that was in the heyday of doing distributed control on DeviceNet.

Never underestimate the eagerness of a customer to discard their backup configuration files and documentation.

Interesting module, but I'm thinking of something even simpler, like an octal-base timer relay with a bunch of DIP switches that could be adjusted to choose various AND/OR/XOR/etc functions. For the actual logic I posted, I could achieve that with 1 SPDT and 1 DPDT relay per set of 2 I/Os, but the relays and bases and labor all adds up pretty quick into something that is very inflexible in the future while still costing as much as a small PLC.

Are the EZ Automation Nano/Micro bricks worth looking at? A couple of those would end up being around the same price as the Click or ProductivityOpen controller and P1000 modules.

 

[the_msp]

https://www.phoenixcontact.com/en-gb/products/relays-and-optocouplers/logic-modules

https://www.youtube.com/watch?v=g3iPFiLnqYg

https://uk.rs-online.com/web/p/plc-accessories/8987674

 

[j.sowin]

Eaton Easy programmable relay, perhaps? Come default with 12 DI and 4 Relay Outputs but can be expanded with relatively inexpensive modules, and the programming software (easySOFT 7) is fairly intuitive and powerful.

 

[ASF]

Never underestimate the eagerness of a customer to discard their backup configuration files and documentation.

I see you've played "engineers and customers" before

I'd also lean heavily toward the Click for this application, but of course if you can't get your hands on one that's probably not terribly helpful.

 

[rjk_cmh]

Eaton Easy programmable relay, perhaps? Come default with 12 DI and 4 Relay Outputs but can be expanded with relatively inexpensive modules, and the programming software (easySOFT 7) is fairly intuitive and powerful.

Looks like an interesting solution, still doesn't really compare to what I have found so far with regards to $/point.

I'd also lean heavily toward the Click for this application, but of course if you can't get your hands on one that's probably not terribly helpful.

So the ProductivityOpen solution appears to be my cheapest option, but I'm a ladder logic programmer and I cannot figure out how this ProductivityBlocks thing works. If I am understanding it correctly, I should be able to make 1 reusable function that contains my XNOR and NAND functionality, and then pass an array of inputs and outputs to evaluate and modify. But I have been bashing my head against a wall trying to make sense of this IDE, and it just is not 'productive' at all especially with no undo function!

 

[ASF]

No undo function? Oof.

I've not used the Productivity series, only the basic Koyo, which is (while somewhat limited) quite user friendly.

 

[Puddle]

How much is the ProductivityOpen option?

The cheapest that I've used is the Siemens Logo controller at a square £100 for the model with no display, plus two digital I/O units (8DI, 8DQ) at £102 each, so £304 total, probably less if your supplier offers discounts.
Next step up is an S7-1211 with one I/O module (16DI, 16DQ) for £520, assuming you have TIA basic.

 

[Zimmer]

or two of these 10 input/10 output, free software

https://ie.rs-online.com/web/p/plcs-programmable-logic-controllers/1232106

 

[rjk_cmh]

No undo function? Oof.

I've not used the Productivity series, only the basic Koyo, which is (while somewhat limited) quite user friendly.

To be clear, this is not a problem with the "big boy" Productivity 1000/2000/3000 series, but rather only with "ProductivityOpen" which uses the Arduino IDE with a skinned version of ArduBlocks for the graphical bits. It's this part that has no undo, although the text portion of the Arduino IDE does of course.

How much is the ProductivityOpen option?

The cheapest that I've used is the Siemens Logo controller at a square £100 for the model with no display, plus two digital I/O units (8DI, 8DQ) at £102 each, so £304 total, probably less if your supplier offers discounts.
Next step up is an S7-1211 with one I/O module (16DI, 16DQ) for £520, assuming you have TIA basic.

I'm currently looking at the following:
P1AM-100 (Arduino-compatible CPU) - $66
P1-16ND3 (16 input module) - $74
P1-08ND3 (8 input module) - $46.50
P1-15TD2 (15 output sourcing module) - $71
P1-08TD2 (8 output sourcing module) - $45.50
Total - $303 USD, all in stock.

or two of these 10 input/10 output, free software

https://ie.rs-online.com/web/p/plcs-programmable-logic-controllers/1232106

Interesting and very compact looking modules, not sure where the 10th output is on that module but maybe they count the modbus port as part of that. Outputs are only numbered from 1-9.

 

[Zimmer]

Interesting and very compact looking modules, not sure where the 10th output is on that module but maybe they count the modbus port as part of that. Outputs are only numbered from 1-9.

Yes, I think it's 9 outputs, I have used them before on a few small projects, they are a rugged little device, despite the small form factor.

 

[rjk_cmh]

OK, here's how it's going to happen. This thing is less than $100 and has all the I/O I need: https://www.amazon.com/gp/product/B07SWZ12BN/

I "found" a copy of Gx Works2 which apparently can be used to program this off-brand board, and that supports ladder which I like. This is for a non-critical application (indicator lights) so I don't care that it is a cheap unknown brand with questionable support. If I have any issues I will update, otherwise we can consider this one solved.