Adding minutes to date time not working properly

问题

I am working on Yii2. In it I am trying to insert data into 3 different stages. i.e. I am using 3 queries one by one to insert different types of data. The data insertion is perfect but date-time is not. As I want to add data continuously so I have added a for loop. But the date-time it's inserting is always the same. See my code below

for ($i = 0; $i <= 60; $i++) 
{
  $dt = date('Y-m-d H:i:s');
 $model401->data_date_time = date('Y-m-d H:i:s', strtotime('+5 minutes', strtotime($dt)));
 $model402->data_date_time = date('Y-m-d H:i:s', strtotime('+10 minutes', strtotime($dt)));
 $model403->data_date_time = date('Y-m-d H:i:s', strtotime('+15 minutes', strtotime($dt)));
.
.
.
.
.
.
}

The date-time is saving in DB is same i.e.

2020-04-25 11:11:57 first record date

2020-04-25 11:16:57 second record date

2020-04-25 11:21:57 third record date

2020-04-25 11:11:57 fourth record date

2020-04-25 11:16:57 fifth record date

2020-04-25 11:21:57 sixth record date

Table View

Update 1

for($i=0; $i<=60; $i++)
{
try {
            $cust_met_data = Yii::$app->db->createCommand(
            /** @lang text */ "SELECT m.`meter_id` , m.`msn` , 
                  m.`cust_id` , m.`device_id` FROM `mdc_meter_cust_rel` m ")->queryAll();
        } catch (Exception $e) {
        }

        $slave_id = $cust_met_data[0]['device_id'];
        $address = 0;
        $count = 14;
        $msn = $cust_met_data[0]['msn'];
        $cust_id = $cust_met_data[0]['cust_id'];

        // my base URL
        $api_url = 'https://localhost:44337/api/rtu/GetData/' . $slave_id . '/' . $address . '/' . $count;


        $curl = curl_init($api_url);

        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_TIMEOUT, 1000);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

        $curl_response = curl_exec($curl);

        $json = json_decode($curl_response);

        if ($json->{0} == '06') {
            echo " line 1656 ";
            echo " An error occurs ";

            //return $this->redirect(['index']);
        } else {
            echo " line 1663 ";
            $vol_1 = $json->{0};
            $vol_2 = $json->{1};
            $vol_3 = $json->{2};
            $curr_1 = $json->{3};
            $curr_2 = $json->{4};
            $curr_3 = $json->{5};
            $kwh = $json->{6};

            $dt =  date('Y-m-d H:i:s');
            $currDt = date('Y-m-d H:i:s', strtotime('+5 minutes', strtotime($dt)));
            $volDt = date('Y-m-d H:i:s', strtotime('+10 minutes', strtotime($dt)));
            $kwhDt = date('Y-m-d H:i:s', strtotime('+15 minutes', strtotime($dt)));
            $typeCurr = "401";
            $typeVol = "402";
            $typeKwh = "403";

            /***** for current *****/
            echo " adding current values ";

            $model401 = new MdcmetersData();
           // $model401->load(Yii::$app->request->post());
            $model401->data_date_time = date('Y-m-d H:i:s', strtotime('+5 minutes', strtotime($dt)));
            $model401->device_id = $slave_id;
            $model401->msn = $msn;
            $model401->cust_id = $cust_id;
            $model401->voltage_p1 = "";
            $model401->voltage_p2 = "";
            $model401->voltage_p3 = "";
            $model401->current_p1 = $curr_1;
            $model401->current_p2 = $curr_2;
            $model401->current_p3 = $curr_3;
            $model401->kwh = "";
            $model401->d_type = "401";
            $model401->save();


            /***** for voltages *****/
            echo " adding voltages values ";


            $model402 = new MdcmetersData();
            //$model402->load(Yii::$app->request->post());
            $model402->data_date_time = date('Y-m-d H:i:s', strtotime('+10 minutes', strtotime($dt)));
            $model402->device_id = $slave_id;
            $model402->msn = $msn;
            $model402->cust_id = $cust_id;
            $model402->voltage_p1 = $vol_1;
            $model402->voltage_p2 = $vol_2;
            $model402->voltage_p3 = $vol_3;
            $model402->current_p1 = "";
            $model402->current_p2 = "";
            $model402->current_p3 = "";
            $model402->kwh = "";
            $model402->d_type = "402";
            $model402->save();


            /***** for kwh *****/
            echo " adding kwh values ";

            $model403 = new MdcmetersData();
           // $model403->load(Yii::$app->request->post());
            $model403->data_date_time = date('Y-m-d H:i:s', strtotime('+15 minutes', strtotime($dt)));
            $model403->device_id = $slave_id;
            $model403->msn = $msn;
            $model403->cust_id = $cust_id;
            $model403->voltage_p1 = "";
            $model403->voltage_p2 = "";
            $model403->voltage_p3 = "";
            $model403->current_p1 = "";
            $model403->current_p2 = "";
            $model403->current_p3 = "";
            $model403->kwh = $kwh;
            $model403->d_type = "403";
            $model403->save();


        }

    }
    }

You can see that first to 3rd and fourth to sixth date-time are the same. How can I set the date-time accurately?

Any help would be highly appreciated.

来源：https://stackoverflow.com/questions/61421783/adding-minutes-to-date-time-not-working-properly