RS232 Protocol - Controller SW1 in RS232 Position
The DPD75601 is a DCE device, therefore it will transmit on pin 2 and receive on pin 3 of the DB9 RS-232 connector. The RS232 serial communication mode is single ended. This means that for each signal there is one wire, and a common ground reference used by all the signals. The DPD75601 does not use handshaking, thus the CTS and RTS lines are internally connected, and the CD, DTR and DSR lines are internally connected inside the DPD75601. The signal line maintains levels of +5VDC to +15VDC and -5VDC to -15VDC. For a valid logic level in the controller, the voltage must be at least +/- 3 volts. RS232 works at distances of up to 50 feet maximum. RS232 is susceptible to electrical noise, and should not be used in noisy areas. Always use the shortest cable con- nection possible. NOTE: Keep Controller wiring separated from motor cable/wiring.
Where is switch 1 set to?
I have ensured the Buad rate is correct.
What baud rate are you using? We would have more confidence in your answer if you posted your code.
The println function sends a carriage-return and linefeed. The documentation is unclear about whether the linefeed will hinder communications.