This　paper　considers　periodic-sampling-based　event-triggered　consensus　of　single　integrators　over　a　fixed　communication　topology.　Two　different　event-triggered　mechanisms　have　been　proposed.　One　requires　the　communication　of　the　states　among　agents　at　each　sampling　instant,　and　the　other　one　only　requires　the　communication　among　agents　at　every　event　instant.　The　linear　transformation　is　used　to　convert　the　consensus　problem　into　a　stability　problem　equivalently,　and　the　S-procedure　method　is　adopted　to　derive　the　consensus　criteria　for　the　two　event-triggered　mechanisms　under　zero-order　hold　actuator　and　exponential　decay　rate　actuator,　respectively.　Finally,　simulation　examples　are　presented　to　illustrate　the　efficiency　of　the　proposed　theoretical　results.　©　2022　IEEE.