Cheap PlC/smart relay for a thermostat (challenge)

[Sandeep R Mittal]

Hi Allscot,
I am Sandeep R Mittal from Selec Controls Pvt. Ltd. India. We have our subsidiary is US also as Selec USA. I saw your requirement. Our MM1010 and MM1012 will be best suited to your requirement. I am new to this so I don't know where to attach data sheet of the product. But i write you here some basic specs
1. MM1010-T/R-230V or MM1010-T/R-24V
8DI, 5DO (Relay) and 1 AI (TC/RTD), RS485 Interface for downloading and networking
Price USD 70 per unit Ex works Mumbai
2. MM1012-230V or MM1012-24V
6DI, 4DO (Relay) and 2 AI (TC/RTD/Volt/Current selectable), 1AO (Volt/Current), RS485 Interface for downloading and networking
Price USD 90 per unit Ex works Mumbai
If you are interested then pls contact me at
[email protected]
sandeep.r.mittal (Skype id)
+91 750 753 71 74 (Cell No.)
www.selec.com to see all products.
Regards
Sandeep R. Mittal

 

[Sandeep R Mittal]

Hi Okie,
I am Sandeep R Mittal from Selec Controls Pvt. Ltd. India. We have our subsidiary is US also as Selec USA and in Germany as Selec GmbH. I saw your thread. I am new to this so I don't know where to attach data sheet of the product. But i write you here some basic specs
1. MM1010-T/R-230V or MM1010-T/R-24V
8DI, 5DO (Relay) and 1 AI (TC/RTD), RS485 Interface for downloading and networking
Price USD 70 per unit Ex works Mumbai
2. MM1012-230V or MM1012-24V
6DI, 4DO (Relay) and 2 AI (TC/RTD/Volt/Current selectable), 1AO (Volt/Current), RS485 Interface for downloading and networking
Price USD 90 per unit Ex works Mumbai
If you are interested then pls contact me at
[email protected]
sandeep.r.mittal (Skype id)
+91 750 753 71 74 (Cell No.)
www.selec.com to see all products.
Regards
Sandeep R. Mittal

 

[todster]

http://www.cainetworks.com/manuals/webcontrol/WebControlPLCUserGuide3-01-06.pdf
Try one of these. You even get analog inputs for under $50. You'll need TTL relays for the outputs.

 

[partho da]

There are a few options for inexpensive smart relays for thermostats. One option is to use an RFID reader and controller to read the tags on the thermostat's housing and control the relay using an app on your phone. Another option is to use a wireless relay module and connect it to your existing HVAC system.

 

[Zimmer]

There are a few options for inexpensive smart relays for thermostats. One option is to use an RFID reader and controller to read the tags on the thermostat's housing and control the relay using an app on your phone. Another option is to use a wireless relay module and connect it to your existing HVAC system.

I would hazard a guess, that the OP has got his thermostat sorted by now.

 

[partho da]

Cheap PlC/smart relay for a thermostat

There are a few options for inexpensive smart relays for thermostats. One option is to use a microcontroller with an I2C interface. Another option is to use a cheap relay module from eBay or AliExpress.

 

[Tinine]

Firmware:
https://sites.google.com/site/annexwifi/home

Hardware: Any ESP8266 or ESP32

Or for more professional packaging, these guys have distributors:
https://shop.m5stack.com/

 

[TheWaterboy]

Hardware: Any ESP8266 or ESP32
Or for more professional packaging, these guys have distributors:
https://shop.m5stack.com/

I just got into these a little myself. Its quite a capable chip - not quite industrial but impressive and cheap.

 

[Tinine]

Elsewhere there's discussion about Arduino's "Industrial" Portenta.
It has zero galvanic isolation.
24V machine control signals run through voltage dividers for level shifting.

I used to think that I knew what "industrial" meant

 

[TheWaterboy]

Yea, they might be taking some liberties there. There's a couple PI's with that title too. They are more like lite commercial grade maybe. But they are bringing control to places that didn't warrant expensive "Industrial" solutions. The features available in these 9 dollar boards are just too good not to resist playing with.

Someday we may find the hidden firmware "features" that were put into that Chinese silicon when someone triggers it.

 

[Tinine]

I actually use low-cost boards in lieu of overpriced PLCs but I opto-couple the I/O.

One of my favourites is the RPi-Pico (no clunky OS) loaded up with the Picomite firmware.

Easiest thing on the planet to program without the BS.

BASIC interpreter:

https://geoffg.net/picomite.html

The remainder of the flash becomes a "disk drive", similar to DOS. Only 700K with the RPi product but the clones can come with 16MB of flash and so we end up with a 15MB "disk drive"

Craig