adccommunitymod (AutomationDirect) asked a question.
Created Date: March 25,2014
Created By: rday78
**** This post has been imported from our legacy forum. Information in this post may be outdated and links contained in the post may no longer work.****
Going to be starting a new project where I would like to have an analog sensor in a hallway that I would use to control 1-stage of heat and 2-stages of DX cooling. Wondering if anyone has any ideas as far as setting up the ladder logic to accept a setpoint from the c-more and controlling the heat/cooling based on the analog input. Seems I may have an issue with temps moving around quickly and attempting to short cycle. All the toys should be here in a few days and just wanted to get the ideas flowing. Also... any way to get better looking sliders for the interface. The ones available arent the prettiest. Thanks
Created Date: March 27,2014
Created by: AlbertL
Sounds like a good project!
I'm working on something similar, but am also just getting started. What kind of sensor are you using? I'm using the Click RTD input module and an AD RTD1-R01-01 room temperature sensor (Pt100 3-wire). An alternative would be a current input module and 0-20ma room temperature transmitter.
To prevent short-cycling, I'd consider implementing a minimum equipment runtime; i.e. once it's turned on, the furnace or A/C will always run for at least X minutes even if the temperature setpoint is reached sooner. You would also want to have a deadband, so the temperature must differ from the setpoint by a certain amount before the equipment is turned on or off. That would prevent, for example, the furnace turning on at 69.999 degrees and off at 70.001.
Created Date: March 27,2014
Created by: rday78
I picked up the room sensor thermocouple and the 4 channel thermocouple input unit for the Click. Im also working on a c-more panel to make it a little more pleasing to the eye. Im on a tight time budget so im going to use a t-stat for the inputs to the plc for now and work on the ladder logic when i get a chance. Ill post my logic in case anyone else can use it for something
Created Date: April 04,2014
Created by: rday78
Also said I would post the logic. First part is the logic for the animation. Second part is t-stat control. Its basic but it gets the job done. Is there anyway I can make the animation logic a sub routine to keep the clutter down?
Created Date: April 05,2014
Created by: AlbertL
Well.... got it up and running. Things look good so far... need some time to get into the logic and change things up. Using a t-stat to send a signal to the PLC but want to use a thermocouple soon and write the logic for the switching.
Looks sweet - nice job!
I'm sure you have many ideas for enhancements, but one feature you might want to consider is logging equipment runtimes, both for preventive-maintenance scheduling and for estimating energy usage.
Created Date: April 07,2014
Created by: rday78
I like the idea.... will def come in handy. Ill see what I can do.
Created Date: March 25,2014
Created by: rday78
Going to be starting a new project where I would like to have an analog sensor in a hallway that I would use to control 1-stage of heat and 2-stages of DX cooling. Wondering if anyone has any ideas as far as setting up the ladder logic to accept a setpoint from the c-more and controlling the heat/cooling based on the analog input. Seems I may have an issue with temps moving around quickly and attempting to short cycle. All the toys should be here in a few days and just wanted to get the ideas flowing. Also... any way to get better looking sliders for the interface. The ones available arent the prettiest. Thanks