Tandem motors homing with one home switch Mesa 7i96s

Hallo everybody.
This is my first project with Linux CNC and I am not really Linux experienced.
Its about a 3 axis CNC router controlled by a 7i96s Mesa card.
I did succeed configurate homing for X and Z axis which have one motor/joint.
But when I am tryin homing Y axis which has tandem motors with one sensor as Y main, the joints are moving in opposite directions. brrrrrrrrr.
When I skip homing and I am jogging the Y axis everything works perfect.
Can you help please with that issue.
I have a spare sensor to install as Y2 but I feel that that process is even more difficult.
I adjust some screen photos of the pncconf wizard.
Thanks
 

Thanks Tommy,
So If I understand what you said me or I have two steppers plugged in the same port with one home sensor or every stepper could be plugged on different port only if it has its own sensor. 
I add the hal and ini files in case that helps

I just put the same sensor as Y and Y2 and works

al_sur_dionisis wrote:

I just put the same sensor as Y and Y2 and works

It might work but there is no guarantee your gantry is square.
What should happen is the first side to hit the limit switch and stops to wait for the other side to catch up before completing the homing sequence. Squaring can be adjusted in software by altering the home_offset in your ini file (eg a 2mm difference side to side can be corrected by having a 2mm difference in home_offset values.

So now linuxcnc will see both sides get to the home switch at the same time and squaring will not ocurr.
I don't know about your machine but on my plasma gantry it wass possible to push the gantry out of square by 150mm (6 inches) and it would sort itself out when homed.

I guess it depands how accurate you want your machining to be.

Thanks Rod.

I do understand what are you saying. I will install soon the second sensor.