A novel approach to a trigger mode in the GasElectron Multiplier (GEM) detector readout system is presented.The system is already installed at WEST tokamak. The articlebriefly describes the architecture of the GEM detector and themeasurement system. Currently the system can work in twotrigger modes: Global Trigger and Local Trigger. All trigger processingblocks are parts of the Charge Signal Sequencer modulewhich is responsible for transferring data to the PC. Therefore,the article presents structure of the Sequencer with details aboutbasic blocks, theirs functionality and output data configuration.The Sequencer with the trigger algorithms is implemented inan FPGA chip from Xilinx. Global Trigger, which is a defaultmode for the system, is not efficient and has limitations due tostoring much data without any information. Local trigger whichis under tests, removes data redundancy and is constructed tosend only valid data, but the rest of the software, especially on thePC side, is still under development. Therefore authors proposethe trigger mode which combines functionality of two existingmodes. The proposed trigger, called Zero Suppression Trigger, iscompatible with the existing interfaces of the PC software, butis also capable to verify and filter incoming signals and transferonly recognized events. The results of the implementation andsimulation are presented
