If limit stop switches are not available, methods –1 to –4 can be used to home based upon detecting the hard stop limits of an axis. In methods –1 and –2, the axis is moved to the high hard stop or the low hard stop respectively. After the hard stop is detected, the axis reverses direction and the home position is set at the first encountered zero index. In methods –3 and –4, the home position is taken as the high or the low limit stops respectively and no zero index signal is utilized. In general, homing to a hard limit stop produces less reliable results than homing to a limit switch. So, methods 1-30 should be used instead of –1 to –4 whenever possible.
Figure 2: Homing Off the Hard Limit Stops and Index Pulse