Can be SoftwareSerial() with zero?

Hi, I only need to use RX pin for communication. Is it possible to use this on Arduino NANO?

SoftwareSerial(5, 0); // RX and TX pin

I don't want to use TX. Therefore it insert zero.

Do not think so. Pins 0 & 1 are used by the Nano's hardware serial port. You may have a conflict if you use the statement Serial.begin() in your sketch.

Nominate another pin, say 6. Don't connect anything to it if you do not intend to transmit anything. I do this with a GPS receiver to a Nano.

John.

The problem began with the involvement of PMS7003, which consumes about 70-100mA. Can't it be that?

If you create a software serial port using pins 5 & 6, you should be able to receive serial data on pin 5 from the external device. No need to connect anything to pin 6.