NodeMCU Modbus interfacing with Pressure Multi-Switch
Now you have node.begin(1, Serial1), but you can't use Serial1 for RS485 because Serial1 doesn't have RX pin

According to the picture you wired the adapter to RX/TX pin of Serial, but this pins are wired on board to USB for communication with the computer (upload and Serial Monitor). You can't use Serial for RS485 adapter while you are using it for debug prints. 

You can use SoftwareSerial fo example on D1/D2 for RS485. 

Or if you have an USB-to-TTL-Serial adapter then you can use Serial1 for debug prints and Serial for RS485