SDM630 on ESP32 not working

[Jimme2]

Hello and good evening,

I'm new in ESP32 and Modbus and have trouble to get the connection to my SDM630 working at all.
May I ask you to help me? Thanks in advance for your support!

My hardware is a ESP32 devkit v4 with a Max485 and SDM630; as software I use PlatformIO.

What I did up to now:
I made new project in PlatformIO and included SDM and downloaded the example SDM_Live_page_ESP32_hwserial.
Then I included <index_page.h> and all necessary lib-deps like <AsyncTCP.h>, <ESPAsyncWebServer.h>

Now I removed // of #define USE_HARDWARESERIAL in SDM_Config_User.h and defined in Arduino.h the "NOT_A_PIN" to "2" as I assume this is De/Re which is used in line "SDM sdm(Serial, 9600, NOT_A_PIN, SERIAL_8N1, 3, 1); of main.cpp).

I entered my wifi data, compiled the code and flashed the ESP - voila the webpage was working but of course all values are zero and Error counter was increasing. SDM READ ERR. CODE | 4 | code was shown.

Now I powered off and connected ESP with Max485 like this:
GPIO1 (TXd)==> DI
GPIO3 (RXd)==> RO
GPIO2 ==> DE+RE
3.3V ==>Vcc
Gnd ==> Gnd

Then I connected the Max485 with the SDM630:
A ==> A
B ==> B
Gnd ==>G

And re-powered everything incl. SDM630. FYI: at the SDM630 no software changes were made, Modbus settings remained default (Adr 001, Baud 9.6k, Par None,Stop 1).

BUT: Now the Webpage still remained counting read errors and the error code also remaind on "4".
I checked wiring several times and read lot of issues here but finally found no solution to get it working.

I checked with Termite if the ESP sends requests and it seems to be working but somehow nothing comes back...

Please let me know if you have an idea what to check next - thanks in advance.

With best regards
Clemens

[reaper7]

to completely eliminate a possible esp problem, do two things:

1. with Termite (as You do before) try to simulate reply and check if webpage shows updated VOLTAGE for request 01 04 00 00 00 02 71 cb

set Termite as shown below:

paste this reply into termite reply line:
0x01 0x04 0x04 0x43 0x66 0x33 0x34 0x1b 0x38

wait when teermite show this request from esp:

and immediately send prepared earlier reply.

check on web page if voltage is updated.

if yes then

2. check with some logic tester or simple led with resistor if DE+RE is properly controlled via GPIO02 from ESP
   (high state when ESP transmit request and low state when esp waiting for reply from sdm)

[Jimme2]

Good evening Everybody,

Good news first: Its working now - thank you reaper7 for your support!

I followed your suggestions with Termite and the webpage was updated well - so far it seems the code was OK.

As I have no logic tester, I used the LED and got slightly confused:
The DE/RE was pulled down well but somehow the onboard LED on the MAX485 did not flicker at all and I remembered that I read somewhere at the internet, that it should..
So I connected a new MAX485 (luckily I had 1 for spare) and now everything was working - but only as long as I do not connect 3,3V supply line to the MAX485.
Somehow the MAX485 was supplied by RX/TX pins out of the ESP32.
I thought to myself: anyway - it's working now and was happy...

Inspired by my success, I now wanted to read-in the voltages of L2/L3 and modified main.cpp + index_page.h.
I transfered --> and it was not working again 😠

I searched again one more long evening - the reason for my late reply - and realized that the 2nd (and my last) MAX485 was killed also - damned.
It seemed to got killed during transfering the code to the ESP32. Memo to myself: Next time I will disconnected the ESP32 from the converter...

Now I ordered a bunch of them at aliexpress (50 pcs for 12€) and another converter from Amazon for 8€ (yes, quite expensive, but I don't want to wait another 20-30 days for next attempt).
This Amazon item is called DSD TECH SH-U12 and has auto-flowcontrol by MAX13487 Chip + 3 LEDs for TXD, RXD, Power and seems to be good quality. On Ali they are sold for ~2€ 🤦 💸
I roll back my definition of "NOT_A_PIN" from "2" to "-1" and transfered my code (with disconnected converter).
Connected the converter, started power supply and et voilá: it is working - Yippee!

So, from now I will transfer only with a disconnected converter - or has someone a better idea?

Thank you all, especially reaper7 - and keep this project running. Good job 👍
Clemens

[reaper7]

lack of activity. closed