KC868-A4 ,RS232 can not communicate with Max232

[Nantawit]

this week when have free time, make a video tour for you. how to use KC868-A4 RS232->RS485 communicate with third device.

Thank you .I  will  try more because  customer   are  waiting  so  to  ensure  all  can  handle.

[admin]

ok, you can use female RS232-RS485 adapter, add a RS232 cross cable is ok.
   

[admin]

RS232 cross cable.
DB9公： in English: DB9 male
DB9母： in English: DB9 female

[Nantawit]

RS232 cross cable.
DB9公： in English: DB9 male
DB9母： in English: DB9 female

ํYes ,I  think  so  that  from  device  RS232  Female Pin 2 (TX) ,3(RX)  to PIN 3 ,2  of  MAX232 respectively .

[admin]

yes.

[Nantawit]

yes.

Morning  ,I  have  test  already  the  result   is  OK ,can  comunicate  with modbus  device (temperaure and  huminity)  ,firstly  ,tested  with Max232 then  the result  was  OK  and  step  to  test  by  RS232/485 connecting to  modbus  device  the  reading  parameters  were  shown .

     Still  want  to  ask  you  why  your  RS232 on board device  desing  is   FEMALE (difficult to  find the  converter and use more  converters too  so  mostly  MALE  and  USB  is  Micro  it  should Micro.

    Mostly  design  pin 2  is  RX.

Thank  you.

[admin]

because the USB-RS232 cable is male.

[Nantawit]

Good  afternoon ,I  met  the problem that  used  ADC (4-20 mA)  ,6  mA  pass through  but   reading  was 4.70 mA  (digital  value is 963 )  how  about  your  formular  ?.
                          For  0-5 V  it  ok  the formular  is ( read (adc)*5)/4096  .

Why  your   device  has  a small electric shock occurred.

[admin]

Theoretical value: 4mA corresponds to 744, 20mA corresponds to 3720, and 4.7ma corresponds to 874. If measured, it is 963

If the whole interval is too large, one offset shall be reduced during calibration.

you can make a list: 4-20mA Draw a curve for every 0.1mA increase. then you will find a own formula.

[Nantawit]

Thank you,ESP32 ,adc is 12 bit that full scale is 4096 ,right ?,so as you gave 20 mA is 3720 that is it can inject current more than 20 mA ,how much can handle current in this port ?.