CPC H01L 21/67733 (2013.01) [B65G 1/0457 (2013.01); B66C 13/23 (2013.01); B66C 13/48 (2013.01); B66C 19/00 (2013.01); B66F 9/183 (2013.01); H01L 21/6773 (2013.01); H01L 21/67259 (2013.01); H01L 21/67724 (2013.01); H01L 21/67736 (2013.01); B61B 3/00 (2013.01); B65G 2201/0297 (2013.01)] | 12 Claims |
1. A method for operating a conveying system, comprising:
positioning an overhead hoist transport (OHT) vehicle over a first load port;
transmitting a first data to the OHT vehicle, wherein the first data includes information of a weight of a first carrier, a number of workpieces in the first carrier, and a first vertical distance between the OHT vehicle and the first carrier:
applying a first lifting force to the first carrier on the first load port, wherein the first lifting force is determined based on the first data;
moving the OHT vehicle over a second load port;
positioning the OHT vehicle over the second load port; and
transmitting a second data to the OHT vehicle, wherein the second data includes information of a weight of a second carrier, a number of workpieces in the second carrier and a second vertical distance between the OHT vehicle and the second carrier;
applying a second lifting force to the second carrier on the second load port, wherein the second lifting force is determined based on the second data; and
receiving the first data and the second data by a control unit of the OHT vehicle for automatic calculation prior to the application of the first lifting force and the second lifting force;
wherein the first lifting force is a minimum force required to lift the first carrier calculated by the control unit of the OHT vehicle, and the second lifting force is a minimum force required to lift the second carrier calculated by the control unit; and
wherein the first lifting force is different from the second lifting force.
|