Smart Meter Interface MODBUS without MQTT how to access to reading ?

[ScanLabs]

Hello folks,

I'm setting up a point-2-point connection to my dongle for BMS (AP) and a display based on Tasmota LVGL (STA).
All work good, Smart Meter Interface is setup - I can see all the values retrieved on the welcome web page .
Having an MQTT connection, from berry I can pickup what I need

eg.
import json
var sensors = json.load(tasmota.read_sensors())
print(sensors.find("SMA",{}).find("vSOC"))

There's a way to to pickup the same vSOC value when an MQTT broker connection is NOT available ?

Thanks,
Paolo

[nikito7]

Rest Json

http://x/cm?cmnd=status+10

[sfromis]

Or maybe have Berry code to pick up values and send to the destination.

[Tangerino]

Any update? IS there a REST or Modbus interface so that we can connect the device to a BMS system as a slave?

[barbudor]

Just to be sure to understand: you have an dongle connected to your meter and using Scripting/SML to retrieve informations that are the displayed on the web and published over MQTT.
Your meter is NOT MODBUS based.

In that case, indeed Tasmota doesn't provide a MODBUS client interface to allow retrieving NON-MODBUS collected data through MODBUS.
It would certainly be a nice addition and could be handled either by a native driver (all esp compatible) or in Berry (only esp32 familiers)

Note there is a MODBUS bridge feature which allows to convert a serial based MODBUS meter into a TCP based MODBUS but that is not what you are looking for is I get it right. In that mode Tasmota convert TCP based MODBUS read/write to serial MODBUS. The remotely collecte values are not accessible to Tasmota (just passing through)

Regarding REST, Tasmota doesn't have a REST API per se, but it is possible to request through http sending Tasmota commands over http.
Although this is more considered as debug feature that a real opérational feature as it tends to use more cou than mqtt. So we would not advise this way for constant polling.

[Tangerino]

The use case is: I have a IoT device connected to the site and monitoring and controlling energy meters over Modbus. I'd like to monitor and control HVAC equipments. So I was thinking I can connect to the Tasmota firmware over an industry standard protocol such as Modbus, REST, etc. Collect telemetry and send commands. If I understood right, there is a way to 'hack' this, by using "Tasmota commands over http". Where I can find such documentation so I can check if it enough for now? Thank you in advance. I intend to collect data every 5 minutes or so.

[barbudor]

Where it is expected: in the doc about 'Commands'
https://tasmota.github.io/docs/Commands/#with-web-requests