Showing posts with label 8051-8052. Show all posts
Showing posts with label 8051-8052. Show all posts

Sunday, February 05, 2017

Isolated RS232 interface to Microcontroller

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

mail from CS

The the circuit you are referring to is... RS232 with Opto-Isolation
The Blue line indicates the Optical Isolation, no wires or cooper should cross this line. Yes the PC Powers the left side, The supply to the right side is the Microcontroller supply. The Microcontroller will have a +5 and GND use this for the right side of opto. I have no PCB for this. You can make your own PCB using eagle cad. I made this circuit as i could not risk my PC and had no other components. I had to make a high voltage measurement with the PC, so this caution.
Also use the Max232 if you do no need 1KV Optical Isolation.

Here is a interface from RE Smith Inc, the one below is not isolated. They have Isolated versions too.

The RS422S is a fast Async bi-directional RS232 to RS422 interface converter that will operate at data rates up to 115.2Kbps. The unit has jumpers termination, RS232 DTE/DCE selection and, TTL/CMOS operation. The unit has two RJ11/12 connectors an a pin header for power, common TTL/CMOS TX data and RX data.

Discover Circuits - Opto-Isolator Coupler Circuits
RS232 to RS232 Port Powered Optical Isolator: Brochure with schematic in PDF format / (added 7/02). RS232C Circuit has Galvanic Isolation:


Saturday, August 23, 2014

Microcontroller and SBC in Real World

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

you can visit these links.......

DigiThermo Wichit Sirichote

DigiThermo 0-100.0 °C Wichit Sirichote

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.

    Wednesday, May 28, 2014

    Interface 89C52 with 7135

    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 need to have Adobe Acrobat Reader

    You can find it here Microcontroller you can now try to write the code and draw the circuit you need.

    AT89C52 Parallel Interface to ICL7135

    AT89C52 Parallel Interface to ICL7135

    This circuit is an interface between 89C52 of Atmel with 7135 of Intersil.  With This circuit you can read analog data of both polarities you can change the range scale with extra circuits, you can store data on a EEPROM or send them to PC thru RS232 or Comm port.


    Wednesday, March 12, 2008

    Application for 8051 mcu project

    Unique Application for 8051 mcu project ?

    Post by J9

    Look at this place


    This is an answer of mine to an old post - 2006