multiple sensors working with smaller distances but not with larger distsnces

I am using 6 (HC-SR 04)sensors to read distances simultaneously. They are my trigger pins are connected to A6 and echo pins are connected to D7 to D12.

When I dump the following code into Arduino nano and use it for simulation purpose it works fine with smaller distances but when I use it for real-time data collection using those sensors it shows some fixed numbers around 24meters.

Can anybody tell me what is the problem.

Application_Finalised_US_Sensors_ESP8266_BT_DHT11_Compensation.txt (5.65 KB)

yeah, but the final output is showing like 24m.How it could be possible?

See the attachment

A6 (and A7) are analog input only. Use another pin for digital output.