Panel description
1) Front panel
(1) POWER power switch.
(2) WdBm logarithmic or linear measurement mode switch button Each time the button is pressed, the display mode switches between “W†and “dBmâ€, and the corresponding indicator on the right side of the digital display window illuminates.
(3) dB (REL) relative measurement button. Pressing, the corresponding indicator on the right side of the digital display window emits light, and the relative measurement of optical power can be performed. The reference optical power value is the input optical power value Pref when the button is pressed, and the second measured optical power display value is Relative value relative to Pref. Pressing the “WdBm†button releases the measurement method.
(4) λSEL wavelength selection key. Press this button, the upper indicator lights, indicating that the instrument is currently in the wavelength selection state, and its selected wavelength is displayed in the digital display window, and the right nm indicator is illuminated, indicating that the unit is “nanoâ€. At this time, other control keys on the panel do not work except "MEAS" and "RMT".
(5) MEAS measurement key. The upper indicator lights during normal measurement.
(6) ZERO zero key. Pressing this button will automatically zero the instrument and the upper indicator will illuminate until the end of zeroing and the indicator will not illuminate. During auto zeroing, other control keys on the panel do not work except for “MEAS†and “RMTâ€.
(7) AVG average function key. When the indicator above it emits light, it automatically performs multiple measurements and performs averaging to display the average value. When the indicator does not emit light, no averaging is performed.
(8) RH range hold button. When the indicator above it is illuminated, it is in the range holding state, and the non-lighting is in the auto range state.
(9) Five-digit LED digital display window of digital display window. Displays the optical power measurement or (during wavelength selection) the number of wavelengths.
(10) OPTICALINPUT is the light input port.
2) Rear panel
(1) "220V/50Hz" 220V/50Hz AC power socket.
operating
Connect the power cable on the rear panel and set the power switch to “ONâ€. The instrument begins a self-test, illuminates all of the light-emitting devices, and then enters the initial state. The initial state of the instrument is as follows:
a. Measuring method: dBm;
b. Measuring wavelength: 1310 nm;
c. Range (RH): automatic mode;
d. Zero (ZERO): off;
e. Average (AVG): Off.
Measurement preparation
1). Preheat for half an hour after starting up. If the measurement requirements are not high, warm up for a few minutes;
2). Zeroing
Zeroing is mainly to eliminate the effects of residual dark current and weak background light of the photodetector. When zeroing, the input port must be completely blocked (note: the plastic protective cover cannot be completely blocked). It can also be zeroed under weak background light, but the background light power value cannot exceed half of the minimum range value;
When zeroing, you can do it automatically by simply pressing the “ZERO†button. During the zero adjustment process, the indicators above the “ZERO†and “RH†buttons light up. Except the wavelength setting button “λSET†and the measurement button “MEAS†on the panel, the other control buttons do not work until the end of zero adjustment. No light, each control button returns to normal.
3). Setting wavelength
After power on, the instrument automatically sets to a wavelength of 1310 (nm). To change the measurement wavelength, press the “λSET†button, and the indicator above it will light. At this time, the “Digital Display Window†(10) displays the corresponding number of wavelengths (nm). Each time the button is pressed, a selected wavelength is changed. At the same time, it is displayed in the “Digital Display Window†(10). The value can be cycled between 850, 980, 1300, 1310, 1480 and 1550 (nm). After pressing the “MEAS†button, the last displayed wavelength is selected. At the same time, transfer to the measurement state.
4). Connect the FC-PC type test cable connection cable.
measuring
1). General measurement
When the instrument is in the measurement state, the display mode of the measurement data can be selected as “dBm†or “W†according to the user's habits and test characteristics. Press the “WdBm†button to complete, press the button once, and the display mode is “dBmâ€. Or "W" exchange once. Both of these methods are absolute values ​​of the displayed data, and "dBm" is a logarithmic representation of the value in terms of one milliwatt.
2). Relative measurement "dB(REL)"
If you want to get relative measurement data, such as loss measurement, you can use the "dB (REL)" button to achieve. First measure according to the general measurement method (dBm) (get the initial value), then press the “dB(REL)†button (the current measurement value when the button is pressed as the reference point), and then measure the changed optical power data, then The display data is the relative "dB" of the reference point for the initial value of the previous measurement.
3). Range selection and maintenance
When the indicator above the “RH†button does not emit light, it is in the auto range state, that is, the instrument automatically switches the appropriate range according to the magnitude of the measured optical power. Press the “RH†button once, the indicator above it will light, indicating that the instrument is in the range hold state and keep the range when pressing this button. In the overrange and underrange, the “OR†or “UR†indicator will correspond accordingly. The ground is illuminated, and the display number of the "digital display window" is constantly flashing, reminding the user that the appropriate range should be changed. This phenomenon also occurs when the input optical power exceeds the maximum range in the auto range state. At this time, the user must pay attention to the safety of the instrument.
4). Description
There are three ways to measure the optical power of the instrument: W, dBm and dB(REL), that is, linear display mode, logarithmic display mode and relative display mode.
a. Linear display mode (W)
This method is used to measure the absolute value of the optical power in units of watts (W). "W" is a basic unit of measurement of optical power, 1W = 1 × 103 mW = 1 × 106 μW = 1 × 109 nW = 1 × 1012 pW.
b. Logarithmic display mode (dBm)
The optical power value is expressed by the logarithm of the optical power value, and the unit is “decibelâ€. "dBm" is a method for expressing the absolute value of power with a reference point of 1 mW, and its unit is "dBm". That is, 1mW corresponds to 0dBm. The conversion of dBm and mW is as follows:
PdBm=10×lg(Pw÷1mW)..............................(1)
Where PdBm - power value in dBm
PW - power value in mW
c. Relative display mode (dB(REL))
In this way, the first measurement value P1dBm is used as the reference point. After pressing the “dB(REL)†key (refer to 4.2.22), and then the second measurement, the value is Pr, then there is :
Pr=P2dBm-P1dBm(dB)..............................(2)
Among them, Pr - relative measurement readings, in dB
P1dBm - the first measurement reading in dBm
P2dBm - reading with 1mW as the reference point, which means that the indicator above the "dB(REL)" key does not emit light, the unit is dBm.
The instrument automatically completes the (2) operation under the relative measurement state, and the direct reading is Pr, and the unit is dB.
5). Precautions
Before testing, you must have a certain understanding of the wavelength of the measured light and the amount of optical power. The correct measurement wavelength of the instrument must be chosen to get the correct measurement. Do not allow the input optical power to exceed the upper limit of the instrument's measurement range. When the wavelength is not correct (especially if the wavelength is shorter than 1100nm or longer than 1550nm), the input optical power is very strong, the instrument can not display, and the optical power is too strong. The photodetector that will burn the instrument.
The power supply preferably has a ground wire and the input supply voltage must be within the range required by the instrument.
If there is a sudden disturbance of the power supply system, the host display may be abnormal, the buttons on the panel do not work, and should be shut down as soon as possible to ensure that the power supply voltage of the power supply system is normal, and then restart the work.
The optical power input port must be connected and accurately positioned, otherwise the measurement result may be incorrect.
Fives. maintain
Reasonable use and proper storage of the instrument can maintain good performance indicators for a long time and prolong its service life, so it needs proper maintenance:
1) The instrument should avoid strong mechanical vibrations, collisions, drops and other mechanical damage. Good packaging and vibration, rain and waterproof measures must be taken during transportation;
2) The instrument should be kept clean and the working environment should be free of corrosive gases such as acid and alkali. Gently scrub the chassis and panel with a clean towel dampened with water or soapy water. Do not scrub with alcohol, gas oil or other solvents;
3) The light input port is directly connected to the light detector. When removing the cable connection cable, the dust cap should be put on immediately to prevent hard objects, dust or other dirt from touching the photosensitive surface, contaminating and damaging the light detector;
4) prohibit excessive light from directly entering the light input port;
5) The instrument should be stored in a clean and ventilated environment. If it is not used for a long time, it should be energized regularly. In humid seasons or wet areas, the interval between power-on should be shortened;
6) If the instrument fails, it should be repaired or repaired by a professional technician. It is forbidden to dismantle the instrument by yourself.
What is Industrial DTU? Industrial DTU characteristics and application field analysis
What is DTU?
A Data Transfer unit (DTU) is a wireless terminal device that converts serial port data into IP data or IP data into serial port data over a wireless communication network.
Second, industrial DTU characteristics?
D220 is an industrial 4G DTU based on 4G wireless network, the product uses high-performance industrial embedded processor, real-time operating system as the software support platform, to ensure that the data link is smooth at any time, to provide users with high-speed, stable and reliable data transmission. It can be easily and quickly arranged in the industrial site, and can be used in harsh environments.
Hardware features:
Anti-interference design, suitable for harsh electromagnetic environment application requirements
Wide voltage power supply design, support DC5V-35V power input, built-in power reverse protection and overvoltage and overcurrent protection
The serial port can be a service serial port or a data serial port
Supports the many-to-many link configuration between the service serial port and the center
Select industrial-grade devices and optimize electromagnetic compatibility design to meet the requirements of harsh application environments
The D220 supports backward compatible 2G/3G network access based on 4G network.
Built-in hardware watchdog, regular detection mechanism, automatic resetting of abnormal equipment.
Complete industrial environment design requirements, all-metal structure, the whole machine has passed the strict electromagnetic compatibility test, CE certification
Software features:
Multi-center mode/Multi-backup mode (up to five multi-centers/backup centers)
Different serial ports can be used as maintenance or service serial ports, and different service serial ports can be connected to different multi-centers.
Multi-protocol upper development kit support (compatible with communication protocols of multiple DTU manufacturers, which can achieve seamless replacement of DTU)
Supports ICMP and LCP link detection technologies and keeps heartbeat alive, ensuring the stability and reliability of the network and communication
Supports local serial port upgrade and remote software upgrade
Supports TCP, UDP, DUTCP, DCUDP and other connection protocols
Supports multiple encryption modes to ensure secure data transmission
3. Application fields
D220 4G DTU conforms to industrial design, complete functions, stable transmission, widely used in environmental protection, water conservancy, meteorological industries; Industrial control field; Industry and special environment, oil and gas, heating industry, etc.
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Shenzhen MovingComm Technology Co., Ltd. , https://www.movingcommtech.com