If you happen to have a standard actuator around that is powered by 24 VAC the feedback is most probably already 0 - 10VDC. Check with a DMM before you apply an external 10VDC source.
On your CO2 Sensor, Why not just use the same potentiometer input you are currently using just “rescale” the input. What about just using an analog output 0 - 100 % = 0 - 10 VDC and tie your analog meter/display directly to the analog output (might need some current limiting resister)…
Do you have devices for your inputs like CO2 sensor.
They are having some issues with their input conversions right now if that is what your issue is.
I wrote a conversion function that works pretty good.
10 REM RETURNS Y INTERCEPT BASED ON XVALUE
20 REM FIT: Y = MX + B ----------------------------------------------------
30 “Your variable” = ( 2000 - 0 ) / ( 20 - 4 ) * ( “Your Input” - 4 ) + 0
40 IF “Your Input” <= 4 THEN “Your Variable” = 0
50 IF " Your Input" >= 20 THEN Your Variable" = 2000
This is for a 4-20 CO2 Sensor with a 0-2000 range. Jjust swap the 4 and 20 for 0-10 or 2-10 depending on your sensor.
I’m just using potentiometers as simulated inputs
Where are you located at? Id be happy to send you some real but slightly used parts if you are in the USA. I got trashcans full of them…
Jim, I’m at Rosedale Technical College in Pittsburgh. 215 Beecham Drive Pittsburgh PA 15205. I’d really appreciate some controls stuff I could use for my controls class. It would help so much. I’d like to pay shipping.
What do you need?
A Co2 sensor, a couple of 10k thermistors, outdoor temp/humidity sensor, current switch, couple of 24vac relay and relay bases, 0-10vdc damper actuator with feedback, duct pressure sensor,0-10vdc valve actuator with feedback, room temp sensor? a couple of bacnet thermostats (viconics) you can try when maurice gets the bacnet subnet working. Ill see if I have a 24vdc power supply for some 4-20 sensors but not too likely. Anything else?
Jim, yes, some room temp/sliders, co2 and humidity stuff would really help, and anything you send will go to good use… It is really swell of you to help a non profit HVAC school. If you give me your paypal I’d like to pay shipping.
As ioware.io suggested, you can load the 2heat/2cool program as a starting point. There may be some shuffling of the IO around required since it was programmed on a Tstat10.
There’s no easy way to move IO around other than renaming them. You can save a bit of time with the programing though, before doing any renaming of IO you can save the program as a .txt file first. After you have shuffled the around by renaming them you reload the original .txt file back into the control basic editor and send to the controller.
How can I get you something for you to review.
aaron.miller( at ) rosedaletech(dot) org
Here’s our first crack at the demo board. I will get a sample off to you for some closeup feedback. I know we need more space for some labels & graphics. Maybe a stand of some sort.
When you have something to share on the lesson document that goes with this I have a friend in Korea who is keen to get started.
Wow! I love the Inputs and the voltage output displays…
So 5 inputs we can make outside air, room temp, setpoint, supply air temp and co2?
Step one of any project to enter a name and range for each of the sensors wired into the system. Give each input a long 20 char name at Tab1 and a short name used for the programming at Tab2. Then set the range for each of the sensors. Since this project uses pots to simulate the readings, and your pots are probably different that what we used here you will need to tweak the range using custom tables. You can read how to do that here:
I haven’t figured out which potentiometer to use with 10v to do 0-10v input yet but to simulate 10k thermistor, a 100k pot in series with 5k resistor works perfect for a range somewhere around 0-100degF
How to use AO to test AI 0-10V ？
- Download and install T3000 on your PC ,link T3-Controller & PC to the same local network , run
T3000->Discover to get T3-Controller under local network in T3000 .
T3000 download address :
2.Basic function of AIs and AO
AI1: connect to ON/OFF switch , Simulate occupied sensor .
AI2–6: wired to 4.7K fixed resistor and 100K potentiometer .
Simulate 4.7K—104.7K devices .
AI7–11: Universal input which can be set as 10K thermistor ,0-5V,0-10V and 4-20mA .
Output 0-10V voltage
- Wired AO5 to AI11, set AO5 & AI11 range as 0-10V ,output a fixed voltage to test AI .
T3000->Outputs->Output11 , Output11 is AO5 .
Output11 is AO5 , the setting is shown .
Auto/manual : Manual
HOA Switch : AUTO
Value : 5.00
Auto/manual : Auto
The value of AI11 is 5.05 V ,which can correctly measure AO’s voltage .
How to set your AI custom range table ?
- Circuit diagram
- Adjust voltage from 0.95v to 2.7V, click T3-Controller and build your custom range table . T3000-> inputs ->custom range
Supply temp, Setpoint and Room temp: 40F to 90F ,
0.95v & 2.7v corresponds to the 90F & 40F .
- Table 3 applied to Supply temp, Setpoint and Room temp .
Love the PC Board Concept! Keeps things very tidy and easy to work with! Great Work!
Let’s get back to the lesson documentation that goes along with that. Post whatever you can and I will get this new demo off to you.