Configuring Constellation Modulator Block for BPSK

Hi,

I'm implementing a BPSK modulation simulation on GNURadio Companion by following the tutorial on PSK Demodulation here: https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation#Adding_a_Channel

I have problems trying to get a clean BPSK constellation graph at the output. This is how I configured the block "Constellation Rect Object" : 

Link to BPSK flowgraph

I'm relatively new to DSP and GnuRadio. Would appreciate if anyone could help me out with the correct configurations in order to implement BPSK modulation. Thank you!

Regards 

GH