Convert 8 bit TTLogic to RS-232c

Discussion in 'General Electronics Chat' started by kuttiess, Mar 2, 2012.

  1. kuttiess

    Thread Starter New Member

    Mar 2, 2012
    Good day to you all.This is Prakash with you.Now im involving in a project,that is to moniter the thickness variation of our producion material during continous process. For that i plan to use three numbers of optical displacement sensors and one omron PLC.
    Now im in trouble to communicate the sensors to the PLC, because they are analog sensors with TTL 3 STAGE 8 BIT OUTPUTS.Now i want your guidance to convey the data which is from sensor as 8 bits to PLC through rs-232c with the help of micro controllers.From google and in this forum i came to know MAX232,but it has TTL TX,and TTL RX as input pins. so, i came to understand before MAX232 i need to do something.
    Basically i am a Mechanical engineer so,i don't have much experience in electronics.But i hope, your guidance will help me to make that.
    I also attach pinout details of that sensor for your reference.
  2. davebee

    Well-Known Member

    Oct 22, 2008
    A microcontroller may be a good way to do this task.

    It does not sound difficult for someone skilled in programming microcontrollers, but for someone who is not skilled in them, there would be a lot to learn.

    I would suggest that you try to find someone with microcontroller experience to either build and program the microcontroller circuit, or help you to do those tasks.
  3. dimulec

    New Member

    Mar 3, 2012
    So, the sensor outputs 8 bit of data, which you can feed into a microcontroller and then programmatically forward it to UART. If you are not going to receive anything back from UART then all you need is a RX connection on the UART side connected to one of the TTL inputs of max232. The corresponding output of this channel will go to whenever you need to connect the RS-232 signal (PLC?). Say, you connected the RX output from the microcontroller to pin 11 of max232. Then pin 14 will be your output to PLC. All max232 does is shifts the voltage from TTL level to +- (6-12)V according to RS-232 specs. There are other solutions as max232 from some manufacturers could be expensive.

    The questions are:
    1. Your sensor is povered by +-15V power supply. Doed it output TTL levels on data lines? If not then you will need to provide a circuit to convert +-15V into 0-5V TTL levels.
    2. Can you write a simple microcontroller program which will read a parallel port and push the data into UART? It is not hard and would be a good learning point.
  4. kuttiess

    Thread Starter New Member

    Mar 2, 2012
    Hi to all,
    Thanks, for your responce, now im in lunch break.Basic of my job is Maintenance.Ofcourse I know,i need to study more about electronics to do something before.This site video tutorials,are really very useful to me.I hope,i will pick up soon.
    Then,Mr. Dimulec,im sure the sensor output is TTL level (0 5v).Thanks for your suggestions.Give me sometime to understand what you say.