Which PLC should be used for Heat Pump and Radiant Cooling?

BirchwoodBill

In Zone 6A. I am looking into hydronic radiant ceiling panels for a new house design to do both heating and cooling. plus an HRV with dehumidifier to handle the latent load. Been through Robert Beans material, Siegenthaler’s material, Caleffi idronics, and various heat pump system manuals.. Was wondering which PLC are being used for heating and cooling applications. Any recommendations?

A PLC is Programmable Logic Controller, like a Dixell iPro, Carel, Allen-Bradley micrologix.

pecmsg

The biggest issue with PLC controls is finding someone that knows how to work on them.

The next is availability of parts!

I had a client here that waited 3 weeks for a new Carel controller programmed!

BirchwoodBill

I think Carel uses c-suite for the programming, Looks like CoDeSys, not ISAgraf.

ratio

Someone here has used the TECO SG2 from FactoryMation (https://www.factorymation.com/SG2_PLR_Smart_Relay) for boiler integration. The programming software is freely available; the hardware looks to be an intermediate between a box pf relays and an industrial PLC. I keep meaning to get one to play around with, but I always get distracted before I convince myself to pull the trigger.

Jamie Hall

rayshare said:

The biggest issue with PLC controls is finding someone that knows how to work on them.

And the second biggest issue is documentation. When the initial setup and programming is complete, well and good -- and five years down the road the poor sap trying to run the thing wants to know how it works and the initial guru is long gone, just what do you do? Throw it in the trash and get something which works...

Zman

You might check out Tekmar for a pre-canned solution. I know they have t-stats that will heat/cool and take humidity/dewpoint into consideration.

BirchwoodBill

Thanks for input. The SpacePak LAHP uses a Carel PCO; Messana uses Emerson IPro genius; RenewAire uses Carel PCO. It looks like spare parts for Carel are more available than Emerson or Dixell.

Starting to look at PoE Tstats that talk Modbus/TCP, don’t know if Tekmar is using Ethernet these days.

offdutytech

I would take a look at BacNet controllers there is more offerings for your application. Easy IO is another basic controls line. I was really never a fan of Carel stuff especially when I did DDC work full time. Niagara controllers are prob the best open protocol controllers for mixing and matching devices and making custom programs. With that said a written sequence of operation is key to follow up years later when somethings not working and you have to follow up behind another tech. 

BlueGreen

I have built monitoring systems with some control outputs with these. The software is free (all I needed) or can be purchased with some additional functionality. If you can do some basic drag and drop logic and simple spreadsheet-like formulas, you can program one of these for all of your inputs and outputs.

https://www.datanab.com/products/mbus_io12_lcd-fully-programmable-modbus-i-o-device-with-lcd-display

BirchwoodBill

Looking at something similar but a small touch screen that is powered by PoE. Need to see if I can fit a HAP interface into firmware for lighting control.

This looks intriguing….

https://www.distech-controls.com/

Jamie Hall

At some risk of sounding like an antique curmudgeon, but with -- I assure you -- truly horrendous experiences in trying to cope with "legacy" software and hardware which wasn't completely -- and I do mean completely -- documented (particularly anything machine or assembler coded, or dependent in some way on customized hardware) -- I would assure you or warn you that unless that is done, what you are building/creating will be fun or practical for you and, bluntly, utterly and completely useless for anyone else. I do not mean to knock your efforts. I applaud them. But you must assume that, to give an example, an elegant control system for your domestic heating will be junked by whomever has to work on it after you.

Sorry...

jad3675

Jamie Hall said:

At some risk of sounding like an antique curmudgeon, but with -- I assure you -- truly horrendous experiences in trying to cope with "legacy" software and hardware which wasn't completely -- and I do mean completely -- documented (particularly anything machine or assembler coded, or dependent in some way on customized hardware) -- I would assure you or warn you that unless that is done, what you are building/creating will be fun or practical for you and, bluntly, utterly and completely useless for anyone else. I do not mean to knock your efforts. I applaud them. But you must assume that, to give an example, an elegant control system for your domestic heating will be junked by whomever has to work on it after you.

Sorry...

(Side-eye look at pile of code and processes for service integration with zero comments, no documentation and an AWOL developer) - that never happens, not even in a business environment!

Friend at work has a really nice HomeAssistant setup at his house. We joke that if he ever gets hits by a bus, his wife will have zero idea how any of it works or how to keep it up.

John

pecmsg

Keep

It

Simple

BirchwoodBill

Thanks for the guidance. The specs for the lighting control is going to Lutron RA3 so that should to follow the KISS principle. Not mixing lighting and HVAC they are separate systems. Will be using HomeBridge for any energy management or integration work.

No custom hardware, I ripped out a custom panel and replaced it with standard taco controls recently.

For this new house…The specifications have been updated for Messana RayMagic NK in the ceiling and Warmboard in the bathroom floors. The Messana ATU can easily handle the latent heat/humidity. The Messana mControl, mZone and mTouch are also specified. Belimo valves and damper controls appear to be very robust and support 24 VDC interfaces.

My background is in industrial automation, so this approach seems very simple and straightforward.
Will need to print out the ladder and function block diagrams from ISAgraf for the Operating and maintenance guide.

elementaries and overall schematics will be done in Visio and the control strategies in MS-Word. Will need to have a panel pc in the utility room that can run troubleshooting software so repairs can be made quickly. Communication will be Ethernet or RS485 - primarily Modbus.

I currently carry spares for the Taco controls in the current house, so I figure the new house will need the following spare

Zone controller
pumps
ECM motors
zone valves
Damper actuator
Sensors
I/o boards.

Any other spares recommended?

ratio

BlueGreen said:

I have built monitoring systems with some control outputs with these. The software is free (all I needed) or can be purchased with some additional functionality. If you can do some basic drag and drop logic and simple spreadsheet-like formulas, you can program one of these for all of your inputs and outputs.

https://www.datanab.com/products/mbus_io12_lcd-fully-programmable-modbus-i-o-device-with-lcd-display

I ended up getting one of these to play around with at work. Attached is an electric heat sequencer program with the following features:

• three separate, prioritized, heating stages
• direct & reverse acting analog outputs for modulating heat use
• three heat output relays with programmable trip points for staged-heat use
• an alarm relay to annunciate (configurable) out of range thermostat inputs and optionally disable all outputs
• user-programmable P, I, & D bands
• all setpoints hidden in an admin screen
• default screen that shows inlet & outlet temps, & heating command
• All setpoints, inputs, & outputs available via Modbus
• all three heating stages usable as either a target discharge air temp or as a ΔT from the inlet temperature!

I'm quite pleased with that last item! My though is that it'll be used for electric reheat-style dehum, add SCR heat strips after an evap coil, a temp sensor in the return air (before the coil) & one after the heat strips, then I'll be able to do a setpoint of something like "-5" & the supply into the room will be 5° cooler than the return air after a pass through the evap & reheat. I expect it to save energy by minimizing the added heat vs just a flat discharge temp of say 70°, and improve comfort by keeping the room temperature from climbing quite so fast.

Or not, IDK for sure.

It's also about half the price of the T775 I was using for this application, although it'll take more jellybeans to hook everything together.

I used all of the relay outputs, half the analog outputs, over half the universal inputs, and around 40% of the onboard resources. The programming software is here (I used the free version 509). I've got maybe 10-20 hours in it all together, but that includes a lot of dinkin' around to see what happens when I do things.

NB: I ran this version via the software's built-in emulator & it seems to work. I ran an earlier version on the hardware & it seemed to work right as well, but YMMV. Also, I may have guessed wrong about the default state of the F/C flag.

JakeCK

jad3675 said:

(Side-eye look at pile of code and processes for service integration with zero comments, no documentation and an AWOL developer) - that never happens, not even in a business environment! Friend at work has a really nice HomeAssistant setup at his house. We joke that if he ever gets hits by a bus, his wife will have zero idea how any of it works or how to keep it up. John

What's a comment?

I run home assistant at my house to control just about everything at this point. But I followed a very simple rule when putting everything together. One that is even simpler then KISS. 

Can Grandma use it?

I always imagine that my computer hating grandmother was still alive today and had to turn a light on or use one of these smart devices. If it fails this test it needs rethought. I could kill the vm running HA right now and the only things that would cease to function with local physical control would be the automations obviously like the timer for the front porch light, etc and the motion floods. And the only reason those would stop working was because I only had 14-2 running to those lights which made it impossible to power the z-wave motion sensor independently of the light. My only solution was to bypass the light switch on one(because people kept turning off on accident! grrr) and leave the switch on the other on all the time like you normally do.