This alarm is generated when both limit proximity switches on the same axis are activated. A simple adjustment to the proximity switch normally corrects this alarm. On this machine the logic is unable to identify the precise switch. This procedure will show you how to locate and identify the proximity switch which is in need of adjustment or has failed.

Locating and Identifying the proximity switches

There is more than one style of Proximity switch but all have a built-in light which indicates the switch’s state (ON or OFF). A metallic block of strip, called a target is placed at the end of travel on each axis. If the switch is over the target the light is OFF. If the switch is not over the target the light is ON.

Isolating the Failing Proximity Switch
Each axis has a plus and minus proximity switch. When looking at the two switches for any axis there are four possible states, three are normal and one generates the alarm. The alarm is generated when both switches of an axis are OFF (indicator not on). All other combinations of ON and OFF are normal operation. To isolate the problem check the plus and minus proximity switch for each axis. Use the photos on page 1 to locate the switches. On the axis that has both proximity switches OFF, the switch that is NOT positioned over a target is in need of adjustment or has failed.

Adjusting a Proximity Switch
The objective is to increase the gap between the switch and the surface it travels over.
If the below steps do not work, please call Park Industries Customer Service at 1-800-785-3391.