Changed FREQUENCY_10HZ to FREQUENCY_5HZ in the ardunio sketch supplied by DfRobot. The update rate did not change.

Here is the final sketch

/*!
@file getLightIntensity.ino
@Set the frequency of data output by the sensor, read the acceleration, angular velocity, and angle of X, Y, and Z axes.
@n Experimental phenomenon: when the sensor starts, it outputs data at the set frequency and the data will be displayed on serial monitor
@copyright Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
@licence The MIT License (MIT)
@author [huyujie](yujie.hu@dfrobot.com)
@version V1.0
@date 2020-12-03
@https://github.com/DFRobot
*/
#include <DFRobot_WT61PC.h>
#include <SoftwareSerial.h>

//Use software serial port RX：10，TX：11
SoftwareSerial mySerial(10, 11);

DFRobot_WT61PC sensor(&mySerial);
long int prevTime = millis();
int resultCount = 0;

void setup()
{
//Use Serial as debugging serial port
Serial.begin(9600);
//Use software serial port mySerial as communication seiral port
mySerial.begin(9600);
//Revise the data output data frequncy of sensor FREQUENCY_0_1HZ for 0.1Hz, FREQUENCY_0_5HZ for 0.5Hz, FREQUENCY_1HZ for 1Hz, FREQUENCY_2HZ for 2Hz,
// FREQUENCY_5HZ for 5Hz, FREQUENCY_10HZ for 10Hz, FREQUENCY_20HZ for 20Hz, FREQUENCY_50HZ for 50Hz,
// FREQUENCY_100HZ for 100Hz, FREQUENCY_125HZ for 125Hz, FREQUENCY_200HZ for 200Hz.
sensor.modifyFrequency(FREQUENCY_5HZ);
Serial.println("DfRobot Test setup FREQUENCY_5HZ");
}

void loop()
{
if (sensor.available()) {
resultCount = resultCount + 1;
if (resultCount > 5) {
exit(0);
}
long int curTime = millis();
long int deltaTime = curTime - prevTime;
prevTime = curTime;
Serial.print("deltaTime "); Serial.println(deltaTime);
Serial.print("Acc\t"); Serial.print(sensor.Acc.X); Serial.print("\t"); Serial.print(sensor.Acc.Y); Serial.print("\t"); Serial.println(sensor.Acc.Z); //acceleration information of X,Y,Z
Serial.print("Gyro\t"); Serial.print(sensor.Gyro.X); Serial.print("\t"); Serial.print(sensor.Gyro.Y); Serial.print("\t"); Serial.println(sensor.Gyro.Z); //angular velocity information of X,Y,Z
Serial.print("Angle\t"); Serial.print(sensor.Angle.X); Serial.print("\t"); Serial.print(sensor.Angle.Y); Serial.print("\t"); Serial.println(sensor.Angle.Z); //angle information of X, Y, Z
Serial.println(" ");
}

}