No response from Drok buck PSU UART

[sidtupper]

I'm making a MPPT solar pump controller using a Drok buck PSU (200310) controlled with a UNO R3, as shown in the drawing at https://sidtupper.ca/wiring%20UNO%20R3%20to%20200310.jpg, and using the BuckPSU library. I'm stalled at not being able to communicate with the PSU. Running the library example, on a logic analyzer I can see that commands are getting to the PSU Rx pin but nothing is coming back on the Tx pin. I've tried obvious stuff like swapping Tx / Rx and various baud rates (9600 vs 4800) without success. I'd really appreciate hints on how to get past this.

[MiguelLameiras]

I'm making a MPPT solar pump controller using a Drok buck PSU (200310) controlled with a UNO R3, as shown in the drawing at https://sidtupper.ca/wiring%20UNO%20R3%20to%20200310.jpg, and using the BuckPSU library. I'm stalled at not being able to communicate with the PSU. Running the library example, on a logic analyzer I can see that commands are getting to the PSU Rx pin but nothing is coming back on the Tx pin. I've tried obvious stuff like swapping Tx / Rx and various baud rates (9600 vs 4800) without success. I'd really appreciate hints on how to get past this.

Hello, have you been able to communicate with the PSU? I am having the same issue.

[sidtupper]

Hi, sorry for the late reply. No, I haven't made progress with this. The manufacturer sent me a link to an example "6012 application" but if I recall correctly, I couldn't access it. You could try asking Drok longqipro@foxmail.com for it.

If you solve it I'd really appreciate hearing from you.

[sidtupper]

Also if you haven't already, have a look at comment threads at http://blog.benjames.io/2018/06/29/secret-uart-on-chinese-dcdc-converters/

[MiguelLameiras]

Thanks! I will try to contact Drok.

[MiguelLameiras]

Hi, I got it to work!

It was necessary to change the "-F3-" function in the board to "-00-". To do this, you have to hold the "SET" button and use the up and down arrow buttons in the board to move to "-F3-", then press "OK". Use the arrow buttons again to change to "-00-". There is a detailed explanation on how to do this here: https://manualzz.com/doc/52965331/drok-dc-voltage-regulator--dc-dc-buck-converter-module-10...

Then, drok emailed me the communications protocol below. The line termination needs to contain an /r /n (0x0D, 0x0A).

200310 communicate.pdf

[sidtupper]

Great! Thanks to you I can resume that project after a year hiatus.

[bengineer19]

Great to hear you got it working and apologies that I was unable to help more. Thanks for sharing Miguel🙌

[sidtupper]

The information was there all the time in the Drok documentation but I gave up too soon. Now I can communicate with the PSU with Putty but haven't got it going in my project context. Putty shows that it works with Rx<->Rx and Tx<->Tx, 8N1, at 9600 baud, but the following ESP32 code gets no reply from the PSU:

`#include <HardwareSerial.h>
#define RXD2 16
#define TXD2 17

String psuData;
HardwareSerial PSUserial(2);

void setup() {
PSUserial.begin(9600, SERIAL_8N1, RXD2, TXD2); // psu <-> esp32 serial connection
Serial.begin(9600); // serial monitor rate
delay(500);
}

void loop() {
psuData = "";
PSUserial.write("arv" + 0x0d + 0x0a); // read set voltage
while(!PSUserial.available() ) {
Serial.print(".");
delay(500);
}
Serial.println();
while (PSUserial.available() > 0) {
psuData += PSUserial.read();
}
Serial.print(psuData);
delay(500);
} `

Can you see what's wrong?