diff --git a/apps/secs_server.cpp b/apps/secs_server.cpp
index c5cb37c..b884397 100644
--- a/apps/secs_server.cpp
+++ b/apps/secs_server.cpp
@@ -16,6 +16,7 @@
 #include "secsgem/endpoint.hpp"
 #include "secsgem/gem/control_state.hpp"
 #include "secsgem/gem/data_model.hpp"
+#include "secsgem/gem/e116_constants.hpp"
 #include "secsgem/gem/e90_constants.hpp"
 #include "secsgem/gem/messages.hpp"
 #include "secsgem/gem/router.hpp"
@@ -340,6 +341,30 @@ int main(int argc, char** argv) {
         }
       });
 
+  // ---- E116 EPT state-change emitter -----------------------------------
+  model->ept.set_state_change_handler(
+      [logfn, emit_event](gem::EptState from, gem::EptState to,
+                          gem::EptEvent ev, std::chrono::milliseconds dwell) {
+        logfn(std::string("EPT: ") + gem::ept_state_name(from) + " -> " +
+              gem::ept_state_name(to) + "  (" + gem::ept_event_name(ev) +
+              ", dwelt " + std::to_string(dwell.count()) + "ms)");
+        switch (to) {
+          case gem::EptState::NonScheduledTime:
+            emit_event(gem::e116::kCeidNonScheduledTime); break;
+          case gem::EptState::ScheduledDowntime:
+            emit_event(gem::e116::kCeidScheduledDowntime); break;
+          case gem::EptState::UnscheduledDowntime:
+            emit_event(gem::e116::kCeidUnscheduledDowntime); break;
+          case gem::EptState::Engineering:
+            emit_event(gem::e116::kCeidEngineering); break;
+          case gem::EptState::Standby:
+            emit_event(gem::e116::kCeidStandby); break;
+          case gem::EptState::Productive:
+            emit_event(gem::e116::kCeidProductive); break;
+          case gem::EptState::NoState: break;
+        }
+      });
+
   // ---- Build the SECS dispatch table once -------------------------------
   gem::Router router;
 
diff --git a/include/secsgem/gem/data_model.hpp b/include/secsgem/gem/data_model.hpp
index 9dac587..e5f3c1b 100644
--- a/include/secsgem/gem/data_model.hpp
+++ b/include/secsgem/gem/data_model.hpp
@@ -3,6 +3,7 @@
 #include "secsgem/gem/store/alarms.hpp"
 #include "secsgem/gem/store/carriers.hpp"
 #include "secsgem/gem/store/clock.hpp"
+#include "secsgem/gem/ept_state.hpp"
 #include "secsgem/gem/store/control_jobs.hpp"
 #include "secsgem/gem/store/equipment_constants.hpp"
 #include "secsgem/gem/store/event_reports.hpp"
@@ -41,6 +42,7 @@ struct EquipmentDataModel {
   CarrierStore              carriers;
   LoadPortStore             load_ports;
   SubstrateStore            substrates;
+  EptStateMachine           ept;
 
   // Convenience: VID -> value lookup spanning SVIDs and DVIDs.
   std::optional<s2::Item> vid_value(uint32_t vid) const {
diff --git a/include/secsgem/gem/e116_constants.hpp b/include/secsgem/gem/e116_constants.hpp
new file mode 100644
index 0000000..61af06c
--- /dev/null
+++ b/include/secsgem/gem/e116_constants.hpp
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <cstdint>
+
+// E116 §6 standard collection-event identifiers, one per top-level
+// state.  Equipment fires the matching CEID on transition into that
+// state; hosts subscribe via the existing S2F33 / S2F35 / S2F37 flow.
+namespace secsgem::gem::e116 {
+
+inline constexpr uint32_t kCeidNonScheduledTime    = 1100;
+inline constexpr uint32_t kCeidScheduledDowntime   = 1101;
+inline constexpr uint32_t kCeidUnscheduledDowntime = 1102;
+inline constexpr uint32_t kCeidEngineering         = 1103;
+inline constexpr uint32_t kCeidStandby             = 1104;
+inline constexpr uint32_t kCeidProductive          = 1105;
+
+}  // namespace secsgem::gem::e116