Am working on Particle matter sensor which works on RS485 Interface protocol.
To read the data from the sensor, Command format: aR0
With Arduino Uno, but unable to read the data, as always it prints -1 and 0 on the serial monitor.
I have tried the below three types, each one declaration as the command format. But nothing works.
#define reqn ‘a’
int reqn = 0x61;
char reqn = “aR0”;
What am doing wrong in the attached code?? Also attached the sensor technical literature.
Your reply will be appreciated.
FRT RDM EN.pdf (1.24 MB)
sketch_RDM200.ino (2.51 KB)