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+--- Thread: KC868-A4 ,RS232 can not communicate with Max232 (/showthread.php?tid=1130)
RE: KC868-A4 ,RS232 can not communicate with Max232 - Nantawit - 11-16-2021
(11-16-2021, 04:06 AM)admin Wrote: 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.
RE: KC868-A4 ,RS232 can not communicate with Max232 - admin - 11-16-2021
ok, you can use female RS232-RS485 adapter, add a RS232 cross cable is ok.
RE: KC868-A4 ,RS232 can not communicate with Max232 - admin - 11-16-2021
RS232 cross cable.
DB9公： in English: DB9 male
DB9母： in English: DB9 female
RE: KC868-A4 ,RS232 can not communicate with Max232 - Nantawit - 11-16-2021
(11-16-2021, 04:32 AM)admin Wrote: 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 .
RE: KC868-A4 ,RS232 can not communicate with Max232 - admin - 11-16-2021
yes.
RE: KC868-A4 ,RS232 can not communicate with Max232 - Nantawit - 11-17-2021
(11-16-2021, 06:48 AM)admin Wrote: 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.
RE: KC868-A4 ,RS232 can not communicate with Max232 - admin - 11-17-2021
because the USB-RS232 cable is male.
RE: KC868-A4 ,RS232 can not communicate with Max232 - Nantawit - 11-24-2021
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.
RE: KC868-A4 ,RS232 can not communicate with Max232 - admin - 11-25-2021
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.
RE: KC868-A4 ,RS232 can not communicate with Max232 - Nantawit - 11-25-2021
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 ?.