How to make esp8266 modbus tcp/ip client send sensor values to the modbus poll program?

Using Arduino Programming Questions
1

"I want the ESP8266 to transmit data over Wi-Fi using TCP/IP communication and then display the values on a SCADA system."

2

Modbus TCP has client and server. there is no slave

3

sorry Modbus TCP slave,I mean that client.

4

I think that slave is called TCP server and TCP client is master, am I wrong?
Btw I tried this without success, so also interested in topic.

5

so the esp8266 should be TCP server or TCP client?

slave/server provide data
master/client request data