GE OPTIMA MR360 Service Training page 159

There are five limit switches in the Fixed table.
1. One Home Sensor Limit Switch. Only when cradle moves to the home position, the Home
sensor Limit Switch will be activated to allow the fixed table to be moved up and down. It
can only be accessed for service by removing the top right cover.
2. Two Up Limit Switches and Two Down Limit Switches. (Shows the logic position diagram of
the four limit switch) This diagram shows the logical position relationship of the four limit
switches. Only Up1 Limit Switch locates on the fixed table frame. The other three limit
switches integrate in the actuator. When the table is going down, Down1 LS will be
touched first, then fixed table will stop if Down1 LS is OK. But if the Down1 LS doesn't
work, the table will keep going down, Down2 LS will be touched and the table will stop. It
is same for Up1 LS and Up2 LS. In normal situation, only Up1 and Down1 will be touched.
Up2 and Down2 LS are redundant to assure the table can stop at UP and DOWN limit
position in case Up1 or Down1 LS are broken. The highest position of the fixed table can
be determined by adjusting the position of the UP LS Actuator. Only when the fixed table
is on the top height, the cradle can be moved in and out.
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