Config app Iot MQTT Panel to read data from Modbus IOT device

I want to read/write data using IOT modbus Device EW11 from Elfin ( MQTT V3 and 4) over internet.
- read 2 registers for temperature
-on/off devices
- change temperature / set temp
- broker emqx.com
- Iot MqttPanel android App for interface



over local network is possible to read data from register 81


mbpoll -a 1 -t 4 -r 81 -c 1 192.168.1.138

Protocol configuration: Modbus TCP
Slave configuration...: address = [1]
start reference = 81, count = 1
Communication.........: 192.168.1.138, port 502, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave 1... Ctrl-C to stop)
[81]: 17
-- Polling slave 1... Ctrl-C to stop)
[81]: 17