diff --git a/influxdb_api.py b/influxdb_api.py
index 9380a60..b1c3a9d 100644
--- a/influxdb_api.py
+++ b/influxdb_api.py
@@ -1460,7 +1460,7 @@ def query_SCADA_data_by_device_ID_and_timerange(query_ids_list: List[str], start
         flux_query = f'''
         from(bucket: "{bucket}")
           |> range(start: {utc_start_time.isoformat()}, stop: {utc_end_time.isoformat()})
-          |> filter(fn: (r) => r["device_ID"] = {device_id} and r["_field"] == "monitored_value")
+          |> filter(fn: (r) => r["device_ID"] == "{device_id}" and r["_field"] == "monitored_value")
           |> pivot(rowKey: ["_time"], columnKey: ["device_ID"], valueColumn: "_value")
           |> sort(columns: ["_time"])
         '''