RS232 communication with 18V7 [solved]


I’m trying the serial communication between a PLC and 18V7. First I tried the Pololu serial transmitter V1.3 with the Pololu protocol, send the following 5 bytes command (figure 1.png):
0xAA (170) - 0xD (13) - 0x05 (5) - 0x00 (0) - 0x64 (100).
With Pololu serial transmitter ok, it works (figure 2.png). With the PLC, producing the same command, it doesn’t work (figure 3.png). What do you think I should check to make sure it works? Since, as shown in the figures, the data transmit are the same, and the serial port I configured at the same way.

Thanks in advance to all.

I solved the problem by swapping the TX and RX pin of the serial port of the PLC (TX-> RX, RX-> TX) at the TTL to serial converter.
I need to understand why instead of the PC serial port pins are fine not traded (TX-> TX, RX-> RX), but this problem is solved.

Thank you, sorry.