html에서 서비스파일에 있는 변수 호출할때

ex)

<ion-col>

<button ion-button large color='primary' class="font-md" style="width: 130px;height:50px;"

(click)="ReadWATT()">Read watt</button>

<ion-label class="font-md align-center" *ngIf="ble.errorrate">

{{ble.watt1}}, {{ble.watt2}}, {{ble.errorrate}}%

</ion-label>

</ion-col>