limit homing movement

hello all,

I would wish to limit a rotary axis movement during the homing sequence. The axis has only one home switch and can rotate freely to an infinite angle. The only problem is, I wish to limit the axis movement during homing at +/- 180′ (this axis is beeing used as a C axis on a 5 axis router and a movement over 200° in both directions would tear the spindle cable.
I was thinking of trying to home the axis in one direction but if the travel would exceed 200° search for the home swich in the oposite direction. Is this possible without recompiling the linuxcnc?

have a nice day!
alex

Another option might be to place the home switch a short move from one limit (like 10 degrees), then begin the home sequence with a move of 12 away from the switch, so if it is on the wrong side of it it will be crossed, then continue the home sequence. But I think Andy's cam idea is better.

this is how the problem is solved in the easy way. I am using some rotary units who only have one small reed switch as a homing switch, no other switches and no space for a cam. Homing is performed well as long the operator leaves the machine in the right position or brings it in the right position before homing, but if he forgets about this, the spindle cable could be teared apart. I was also thinking using a comp and "force" homing the axis if the travel during homing excedes a certain value, the operator should notice the homing was not right, correct the position of the C axis and redo the homing.