GPI control box has twelve relay outputs, with maximum switching current of 3A/220V

Programming information:

Com port settings: RS232, 9600 baud, 1 start bit, 8 bits, no parity, 1 stop bit

When a byte is sent, the box accepts higher four bits as address bits, while lower four are information. There are three address combinations:

- 0000 (0h) - outputs 1 to 4
- 0001(1h) - outputs 5 to 8
- 0010 (2h) - outputs 9 to 12

Four lower bits that represent information would trigger the relays


- Sending 00001000b (08h) would switch output four on
- Sending 00000010b (02h) would switch output four off and output two on
- Sending 00010011b (13h) would turn on outputs nine and ten on

Additional command is 10100000b (A0h) on which the GPI box will send status of outputs, totaling of three bytes, in the same format as mentioned above: higher four bits would represent output addresses and lower four their status.

On power up or watchdog reset the box would send a 'wake up' byte 11000000b (C0h).

After each received byte, the same byte is send as back and could be used to test if command was properly received.

GPI Control Box Broadcast Automation Software

Twelve relay outputs

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