Connecting 8 relay module

I have an external 5v wall transformer. The power from that goes to the jd-vcc pin. The ground pin on the outer sockets goes to gnd on breadboard. Does a gnd pin from arduino need to be attached to the gnd pin on the middle pins of the module? Ive also have a gnd pin from arduino going to the gnd on the breadboard.

If I wired this wrong please let me know. Thanks. :slight_smile:

The jumper should be removed and there is no ground wire required going to the Arduino. This will give complete isolation.

dlloyd:
The jumper should be removed and there is no ground wire required going to the Arduino. This will give complete isolation.
http://forum.arduino.cc/index.php?topic=302601.msg2106189#msg2106189

Thanks! So I still need to connect the arduino 5v to the VCC on the board right?

Thanks! So I still need to connect the arduino 5v to the VCC on the board right?

Yes, this provides power to the opto-isolator's IRLED.