details required for... Atmels 89C52 Microcontroller A/D D/A converter Keypad LCD display(Or LED Display) 5V Regulated power supply. Temperature & Humidity controller using PID control algorithm implemented using Atmel's 89C52 microcontroller for a AHU unit ( Analog Input from the sensor(4 wire) 0-10v dc & Output from Microcontroller is 4-20mA to the Actuator through a DAC converter).
The Temperature & Humidity to be controlled are 24±1 degree Celsius and 55%±2% Rh respectively. provide me with good LINKS.
mail from SA
Get a sensor that gives a 0-10V or 4-20mA proportional to RH% and Temp deg C. what you need to do now is to select a A/D and a D/A for a real world interface
Build your own a laboratory instrument for measuring time and temperature. The DigiThermo demonstrates the use of 'C' language, a dual-slope converter, LCD interfacing, and digital filtering as well..
The Assembly language program for this may be the complex, due to PID. and my uC pages micro-delabs also in my other pages you can find theory on PID etc, in them i have MCS51 code for 2 setpoint process controller.
Other uC projects sites links
Temperature and Humidity Meter - This project is a combined temperature and humidity meter. It is an improvement on my PIC-based humidity meter and my PIC and AVR thermometers. I use an ATmega164, which as lots of I/O and memory.
Temperature and humidity measurements with the AVR web-server- The tuxgraphics Ethernet board has a lot of general purpose IO pins where external hardware such as sensors can easily be attached. In this example we use the sensirion sht11 sensor to measure temperature, humidity and calculate the dew point.
One of the books here is The " Intersil Hot Ideas" - This was my Mentor Book These helped me build Intelligent Instruments in the 80s. Intersil( GE) was in advanced CMOS before anybody else. They made the smartest chips when the Microprocessors were being examined Skeptically by engineers. (At that time Microprocessors needed many support chips and consumed huge power only later CMOS uC came)
See also delabs Resources i have created as a reference for such doubts (2007)