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.
i am interested in doing with 89C52. And now I trying to use AT89C52 and ICL 7135. And I use nterrupt 0 to get BCD data from ICL7135. I send you my program here and expect to get your advice soon. post by NHT
I have made a circuit for you to study, also some idea about the code.
You can find it here Microcontroller you can now try to write the code and draw the circuit you need.
I've seen on the net the schematics for RS232 with Opto-Isolation. The supply on the PC side is from the PC. The supply from the line side is external? I've seen the 3 connectors (RX, TX & GND) together with 2 connectors 5V. One of them is connected to the device. How about the other? Needs additional power source?
Could you send me the PCB and component layout, as well as the component list, I'm afraid to get mistaken