A New Remote Monitoring System Application in Laser Power Based on LabVIEW

In this paper, a new remote monitoring system based on LabVIEW was proposed to measure laser power automatically and remotely. This system consists of four basic components: an DH-JG2 optical power meter, a NI-USB 6008 data acquisition card, a personal computer (PC), and HP laserJet 1020 Plus printer. Since power output of laser is generally so unstable that abnormal work situation could not retroaction to inspectors right away, new system was designed to solve this problem. The detection system realized function of remote control by TCP protocol and mobile phone. Laser power curve that is measured by detection system demonstrated that the design has a good performance in real-time detection and operability.


Introduction
Laser is the important component of technologies in the field of communication, manufacturing, as well as optical experiment because of its characteristics including high brightness, good monocolor, good coherence as well as good direction.However, as far application, one of the main problems is that its output power is not stable and the laser is easy to be destroyed because of transient circuit and voltage peak [1].Lots of power meters were invented for measurement in the process of laser manufacture last decades.With the rapid development of the computer technology, manual operation desktop machines have the disadvantages of low efficiency, inconvenient data analysis and storage in the quality of laser testing [2].Therefore, software-based automated testing system design is imperative.Measurement system of laser power in VC++ [3], the software of optical power measurement and calibration and instrument control system based on LabVIEW have overcame the lack of the manual operation desktop machines, but they remains to be more automatical, and errors in the testing process can't be managed when failed in working in time [4].
With the rapid development of the computer technology and the software technology, there are more and more kinds of software development platforms and instrument functions which can be achieved by computers and related software NI-LabVIEW [5].LabVIEW produced by National Instruments is the most widely used as virtual instrumentation system.It has the development and debugging tools of traditional programming language.
The greatest feature of LabVIEW is the graphical programming language, which is easy to grasp, understand develop a friendly, realistic user interface.LabVIEW offers a numbers of source-level instrument drivers, including DAQ, GPIB, PXI, VXI, RS232 as well as USB, users can choose their own hardware drivers according their own needs [6].
In this paper, a remote monitoring system in laser power based on Labview was designed and implemented.
The system used optical power meter DH-JG2 as monitoring laser power component produced by DaHeng.
NI-USB 6008 data acquisition card was utilized to collect the power data from power meter.A electrical energy supply system HSPY_36_03 produced by HSPY was employed for turning on or off the laser, Also HP laserJet 1020 Plus as the output device of the test report.Besides, using the real time software LabVIEW displayed and analyzed the power data, and a mobile phone was used to remotely monitor.

System composition
System design framework is shown in fig. 1, from which we can see the system consisting of Laser, power meter, data acquisition card, printer, PC machine, electrical energy supply system as well as mobile phone.In which, DH-JG2 is the power meter, responsible for collecting the

LabVIEW Program
The LabVIEW has been used to acquire the laser power data obtained from power meter, and display the raw data.
After data of laser's power waveform acquisition, the data are sent to Express Virtual Instruments for signal processing.To evaluate the quality of the laser, the program will find the maximum, minimum as well as average value from the processed signal in order to calculate the stability of laser power.After that, the system needs to generate the test report and output it by printer.Virtual Instrument (VI) provides Report Generation tools and thus the test report is produced.

Data Acquisition
In this system, setting the measurement time interval and the total measurement time are required.After that we can easily read out the measurement results of fixed interval.
Comapared to the traditional measurement of power stability that is measured by inspectors and need recorded measurements within 24 hours continuously, this system can save labor force.The block program of data acquisition is shown as Fig. 2, which includes DAQmx When the power meter and the software connect to the DAQ card [8], we can measure the output the laser power automatically.And the data real-time displayed on the wave diagram, we can realize the trend of power.Fig. 3 shows the front panel structure of the data acquisition, in which the results of Measurement 4.28 is just the measured output power [9].

Data Analysis
The data analysis includes displaying real-time laser power data and extracting the data of the average, maximum, minimum, peak-peak and the stability value.
The stability value was calculated in Equation 1.
Where, w S is the stability of the laser power, and the max P , min P , and a P represent maximum, minimum and average value of the laser power, respectively.The Statistics function was used to get the average, maximum, minimum, peak-peak value of the power data[10].Fig. 4 and Fig. 5 show the front panel procedure and the block diagram procedure of LabVIEW of the laser's power data analysis.In server, using Telnet Create Listen receives the

Furthermore, it has
the powerful signal processing ability, and integrates almost all of the features of hardware communications such as data acquisition card.Virtual instrument is an individual computer testing equipment that has a virtual instrument panel.It brings a revolutionary change in the field of automatic testing system.To a testing platform, LabVIEW includes the storage functions of data collection, processing and DOI: 10.1051/ 06006 (2016) , matecconf/2016 MATEC Web of Conferences 61 610 2016 APOP analysis.To meet the needs of various practical applications toolbox, it can use dynamic link (DLL) technology to users of the virtual instrument software to link to them.use links embedded object (OLE) technology will be embedded in other virtual instruments.
actual laser power data, and outputting voltage signals.And the USB 6008 is a data acquisition card produced by NI(National Instrument), can collect voltage signals from DH-JG2, convert the signals into digital signals and send the digital signals to the PC machine by USB bus[7].On the one hand, PC machine displays and analyses the power data, and generates a test report and sends it to the HP laserJet 1020 plus and then the report would be printed by the printer.In addition, the system can easily to turn off laser through sending the codes to HSPY_36_03 and then laser will stop working until the electrical energy supply down to zero.A mobile phone is needed in remotely monitor system.

Figure 1 .
Figure 1.Framework map of system design

Figure 2 .
Figure 2. The program of data acquisition

Fig. 6
Fig.6shows the working model of the system.Before start testing, the Parameters Setting part that is the details about the laser and the test settings including testing time,

Figure 3 .
Figure 3.The front panel structure of the data acquisition