The 6-way programming connector provides VCC and ground, TTL level serial RX and TX, and I2C SDA and SCL. The serial port is used by Zelio Soft to program the device. Presumably the I2C interface is used by the EEPROM backup modules.
I have successfully programmed this device using the Sparkfun FT232R breakout board set to 5V. I suspect the official programming cable just contains a MAX232 level shifter or similar.
In Zelio Soft’s monitor mode the PLC’s state is polled via the serial port in the programming connector. The protocol used looks like MODBUS ASCII at 115200 bps, 7 data bits, even parity, 1 stop bit (7E1).
Programming Connector Pinout
Viewed looking at the front of the smart relay.
|3||Rxd (serial in)|
|5||Txd (serial out)|
Gustavo has been kind enough to provide pictures of the programming cable. Thanks Gustavo!
It looks like two 211/411op-amps are used to convert between the different signal levels.
Pin out DB9 (F) | Color cable