not NULL chheck

src/plugins/Display/Display.h

@@ -58,7 +58,9 @@ class Display {
     }
 
     void tickerSecond() {
-        mMono->loop();
+        if (mMono!=NULL){
+            mMono->loop();
+        }
         if (mNewPayload || ((++mLoopCnt % 10) == 0)) {
             mNewPayload = false;
             mLoopCnt = 0;
@@ -95,7 +97,7 @@ class Display {
             totalYieldTotal += iv->getChannelFieldValue(CH0, FLD_YT, rec);
         }
 
-        if ((0 < mCfg->type) && (mCfg->type < 10)) {
+        if ((0 < mCfg->type) && (mCfg->type < 10) && mMono!=NULL) {
             mMono->disp(totalPower, totalYieldDay, totalYieldTotal, isprod);
         } else if (mCfg->type >= 10) {
 #if defined(ESP32)