Add checking for ring integrity

If check is not made, ioc will try to write to register in the beginning and fail, crashing the application.

vmmTblApp/src/vmm_tbl.cpp

@@ -20,12 +20,14 @@ VMMTbl::VMMTbl(RMM* rmm, const char *FENPortName, int ring, int node, int hybrid
   createEpicsParams();
   setInitialEpicsParams();
   rmm->updateTopologyPvs(ring, node, "vmmTbl");
-  for (int hyb = 0; hyb < number_hybrids; hyb++) {
-    pVmmTblAPI->enableHybrid(hyb, true);
-    setStringParam(vmmHybFwVersion_[hyb], pVmmTblAPI->readFwVersion(hyb).c_str());
-    setStringParam(vmmHybId_[hyb], pVmmTblAPI->readIDChip(hyb).c_str());
-    setStringParam(vmmHybGeoPos_[hyb], pVmmTblAPI->readGeoPos(hyb).c_str());
-    setIntegerParam(vmmHybLinkStatus_[hyb], std::stoi(pVmmTblAPI->checkLinkStatus(hyb)));
+  if (rmm->getRMMAPI()->checkRings() == rmmSuccess) {
+    for (int hyb = 0; hyb < number_hybrids; hyb++) {
+      pVmmTblAPI->enableHybrid(hyb, true);
+      setStringParam(vmmHybFwVersion_[hyb], pVmmTblAPI->readFwVersion(hyb).c_str());
+      setStringParam(vmmHybId_[hyb], pVmmTblAPI->readIDChip(hyb).c_str());
+      setStringParam(vmmHybGeoPos_[hyb], pVmmTblAPI->readGeoPos(hyb).c_str());
+      setIntegerParam(vmmHybLinkStatus_[hyb], std::stoi(pVmmTblAPI->checkLinkStatus(hyb)));
+  }
   }
 }