Biral VPF Series User Manual
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Biral VPF Series User Manual

Present weather sensors
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VPF Series
Present Weather Sensors
VPF-710
VPF-730
VPF-750

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Summary of Contents for Biral VPF Series

  • Page 1 VPF Series Present Weather Sensors VPF-710 VPF-730 VPF-750...
  • Page 2 The information contained in this manual (including all illustrations, drawings, schematics and parts lists) is proprietary to BIRAL. It is provided for the sole purpose of aiding the buyer or user in operating and maintaining the instrument. This information is not to be used for the manufacture or sale of similar items without written permission.

  • Page 3: Table Of Contents

    The sensors covered in this manual .............. v Features of the HSS sensors ............... vi Customer satisfaction and After Sales Support ..........viii Contacting Biral..................viii Five year warranty ..................ix If you need to return the sensor ..............ix CE Certification –...
  • Page 4 Sensor Features ....................102 Present Weather Measurements ............... 104 Sensor Specifications ..................110 VPF-700 Series of Sensors - Dimensions ............117 INDEX ......................... 118 NOTES: ........................123 FIGURES Figure 1-1 VPF-730 in its packaging ................2 Figure 1-2 Example of VPF-710 and VPF-730 Connectors ........4 Figure 1-3 VPF-750 Connectors ...................

  • Page 5: The Sensors Covered In This Manual

    General Information The sensors covered in this manual: Sensor Model Capability VPF-710 Visibility VPF-730 Visibility Precipitation type identification This model has an extra backscatter receiver for: Rain rate Snowfall rate Precipitation accumulation VPF-750 Visibility Precipitation type identification This model has an extra precipitation sensor and an extra high accuracy temperature and humidity sensor for: 50 weather codes (from WMO...

  • Page 6: Features Of The Hss Sensors

    Thank you for choosing Biral as your supplier of Present Weather Sensors A great deal of time has been invested at Biral to offer the best combination of sensor performance and value and almost three decades of experience and knowledge have been incorporated into the VPF Sensors.

  • Page 7: Contacting Biral

    Customer Satisfaction At Biral we set our standards high and only your complete satisfaction is acceptable to us. If you believe your experience has not met these standards we would be grateful if you would contact us so we can rectify any issues you may have. Equally, if you have any positive experiences you would like to share please contact us.

  • Page 8: Five Year Warranty

    The VPF Present Weather Sensors come with a five year limited warranty against defective materials and workmanship. If you have any questions about the warranty, please contact Biral. In order to help us to assist you please be sure to include the following information:...

  • Page 9: Ce Certification - Safety

    CE Certification - Safety All Biral’s VPF sensors comply with the requirements for CE marking. Once installed, it is the user’s responsibility to ensure that all connections made to the sensor comply with all Local and National safety requirements. In order for the mains version of any sensor to comply with the requirements of EN 61010- 1:2010, ‘Safety requirements for electrical equipment for measurement, control, and...

  • Page 10: Sensor Set-Up

    Note: Many of the tests specified within this manual require the use of a PC or equivalent. To achieve the two-way serial communication required, Biral recommends the use of a PC running the Biral Sensor Interface Software. If this software is not available, use a terminal program - for example Windows® HyperTerminal™. The Biral Sensor Interface Software is available from our website, http://www.biral.com/technical-support/downloads/software-downloads/...

  • Page 11: Step 1 - Unpacking The Sensor

    Section 1 Sensor Set-up 1.1 STEP 1 - Unpacking the sensor Calibration Kit (Option) Documentation Top Layer VPF-730 shown Other sensors will be packed similarly Spaces for VPF-750 accessories Cables, Mounting kit, Temp sensor Bottom Layer Figure 1-1 VPF-730 in its packaging STEP 1 - Unpacking the sensor...
  • Page 12 Section 1 Sensor Set-up Other optional components you may have ordered: Calibration Kit The calibration kit is supplied in a protective carrying case, containing: a calibration screen, mounting arm and connector (referred to as the calibration reference plaque when assembled) and 3 x grey foam plugs. Transit Case A rigid re-usable transit case designed to provide full protection to the sensor for regular shipping.

  • Page 13: Step 2 - Electrical Connections

    Section 1 Sensor Set-up 1.2 STEP 2 - Electrical Connections All electrical connections should be completed before applying power to the sensor. 1.2.1 Cables The VPF-700 series of sensors are supplied with all necessary cables. Generally, two cables are required, one for power and one for data. These two cables are supplied in a standard length of 6m.

  • Page 14: Figure 1-3 Vpf-750 Connectors

    Section 1 Sensor Set-up be correct for the specific sensor and can only be mated with the correct sensor socket for each function. 1.2.3 Sensor Connections VPF-750 Power Input Temperature/Humidity 3 Pin Plug Sensor. 6 Pin Socket Precipitation Sensor 3 Pin Socket Ambient Light Sensor Data Cable 7 Pin Socket...

  • Page 15: Table 1-3 Rs232 Signal Connections

    Section 1 Sensor Set-up 1.2.5 Data Connections – Twin Cable Sensors RS232 Signal Connections When operating in the RS232 interface mode, the output signal cable furnished with the sensor has the following pin and conductor assignments. The cable consists of 3 sets of twisted pairs.

  • Page 16: Table 1-5 Combined Power And Data Connections

    For extreme environments, in particular continual salt spray, even the military specification passivated aluminium connectors can suffer serious corrosion over a few years. Biral can provide a sensor with cables passing through plastic environmentally secure glands as a replacement for the standard connectors. The cables in this option of the sensor are permanently connected to the sensor during manufacture.

  • Page 17: Step 3 - Equipment Test

    Connect sensor earth lug to earth, this may not be necessary but can help prevent communication errors with certain PCs. 2. Connect the signal cable to a PC running the Biral Sensor Interface Software. If this is not available, use a terminal program - for example Windows®...
  • Page 18 Section 1 Sensor Set-up 4. Turn the local power source "ON". If communications are working the sensor will respond with “Biral Sensor Startup”. 5. Check Data Transmission To Sensor: Send the command R? from the PC terminal to the sensor: The sensor will respond with its Remote Self-Test &...

  • Page 19: Step 4 - Configuration Options

    The configuration commands are detailed below in sections 1.4.3 to 1.4.12. An alternative method of configuring the sensor is to use the Biral Sensor Interface Software. The “Sensor Settings” tab provides an easy method of viewing or changing the settings.
  • Page 20 Section 1 Sensor Set-up 1.4.2 Date and Time Stamp in data string By default, the date and time stamp is not included at the start of the data string. This is controlled by the Options Word setting; see 1.4.1 To enable Date and Time stamp The sensor can be configured to generate messages with the date and time string by setting the least significant bit in the options word using the following procedure: 1.
  • Page 21 Section 1 Sensor Set-up To set the current Date and Time There are two commands required to set the current date and time: %SD sets the date. The format of the command is: %SDWDDMMYY where: - is the day of the week (1..7) with Monday being 1 - is the date (01..31) - is the month (01..12) - is the year (00..99)
  • Page 22 Section 1 Sensor Set-up 1.4.3 Message Checksum A checksum byte can be included with messages sent by the sensor to verify that noise in the communications link has not changed the message. Generally, noise is not a problem and checksum verification is not required. Note: if RS485 communications are selected then this checksum is not used.
  • Page 23 Section 1 Sensor Set-up IF <cksum> = 20 THEN <cksum> = 107 IF <cksum> = 33 THEN <cksum> = 94 1.4.4 RS485 Communications Configuration The VPF sensors can use either RS232C or RS422/RS485 signal voltage levels. The configuration of the sensor is selected at time of manufacture. If the signal voltage levels for RS422/RS485 are set either RS422 or addressable RS485 communication protocols may be used.
  • Page 24 Section 1 Sensor Set-up The 2 character sensor address is defined by the operator for the unit and programmed as specified in Section 1.4.5. It can be any numeric value between 00 and 99. It is used by the sensor to identify the recipient of the message.
  • Page 25 Section 1 Sensor Set-up Checksum is calculated as : ASCII string 42D? BYTE Values (in Hex) 34+32+44+3F Sum is E9 One’s compliment (0xFF – 0xE9) = 0x16 Two’s compliment 0x16 + 1 = 0x17 Checksum is 0x17 (Hex) Checksum ASCII characters are “17” Transmitted string will therefore be: :42D?17<CRLF>...
  • Page 26 Section 1 Sensor Set-up Note: When RS485 communications are enabled the sensor will not output the “Biral Sensor Startup” message on power up and reset. 1.4.5 Sensor Addressing – RS485 sensors only To use addressable RS485 communication each sensor must have a unique address in the range 0-99.
  • Page 27 Section 1 Sensor Set-up 1.4.7 Data message type setting The sensor can be set to send a compressed data message or an expanded data message, as detailed in section 2. The default setting is for expanded data message. To check which message is programmed send the message: OSCM? The sensor will send the reply: 00 = Expanded data message enabled...
  • Page 28 Section 1 Sensor Set-up 1.4.9 Window heater operation setting The sensor can be set to have the window heaters disabled, permanently enabled, or for them to be controlled according to contamination levels. The default setting is for window heaters enabled and on. To check which configuration is programmed send the message: OSWH? The sensor will send the reply:...
  • Page 29 Section 1 Sensor Set-up %B4<CRLF> The user then receives a prompt to send an "OK" to the sensor at the new baud rate setting. The new setting will only be accepted if the user manages to communicate with the sensor at the new baud rate within 60 seconds. Otherwise the sensor will reset and continue operation with the original baud rate settings.
  • Page 30 Section 1 Sensor Set-up 1.4.12 Configuring the EXCO Output The way in which sensors report EXCO can be configured using the PEn command to allow the reporting of either EXCO or TEXCO. TEXCO is Transmissometer equivalent EXCO. This is the forward scatter total EXCO adjusted to compensate for the difference in reporting between transmissometers and forward scatter sensors during liquid precipitation events.

  • Page 31: Step 5 - Installation

    Section 1 Sensor Set-up 1.5 STEP 5 - Installation Please consider the following factors when installing the sensor: (1) Siting considerations. (2) Height of the sensor above ground. (3) Orientation of the sensor. (4) Mounting the sensor. (5) Electrical grounding. Each of these factors is covered in more detail below: 1.5.1 Siting Considerations Pollutants –...

  • Page 32: Table 1-7 Recommended Sensor Height Above Ground

    Section 1 Sensor Set-up 1.5.2 Height Above Ground: The optimum height at which to mount the sensor depends on the application. The table below shows some recommended heights. Application Typical height Comment Highway fog-warning 1.5 to 2 metres Recommended height for the systems.

  • Page 33: Figure 1-4 Vpf-710 Orientation

    Section 1 Sensor Set-up VPF-710 Orientation The VPF-710 receiver optics should be aligned with true North (true South in the Southern Hemisphere) as shown in Figure 1-4 VPF-710 Orientation. 068º North (0º) (Sensor Front) Figure 1-4 VPF-710 Orientation VPF-730 and VPF-750 Orientation The VPF-730 and VPF-750 alignment should be such that neither the forward nor the backscatter receiver optics is aligned with the rising or setting sun.

  • Page 34: Figure 1-6 U-Bolt Mounting Method

    Section 1 Sensor Set-up 1.5.4 Mounting the Sensor – All Models The sensor head should be attached at the very top of the mounting pedestal with a U-bolt. The mast should be made from galvanised steel pipe or heavy walled .

  • Page 35: Figure 1-7 Vpf-750 System

    Section 1 Sensor Set-up 1.5.5 Mounting the Sensor – VPF-750 Specific The VPF-750 consists of a VPF-700 Present Weather Sensor, combined with a Precipitation Sensor, a Precision Temperature and Humidity sensor with radiation shield and an optional Ambient Light Sensor. The complete system is assembled as shown in Figure 1-7 VPF-750 System: Precipitation Sensor VPF-750 Present Weather...

  • Page 36: Figure 1-8 Precipitation Sensor Mounting Details

    Section 1 Sensor Set-up 1.5.6 Assembly Instructions VPF-750 On the rear of the present weather sensor, unscrew the small saddle which locates the system onto the mounting pole. Place the appropriate end of the Precipitation Sensor mounting bracket under this saddle and replace. This will locate the Precipitation Sensor immediately behind the back-scatter head as shown in Figure 1-8 Precipitation Sensor Mounting Details.
  • Page 37 Section 1 Sensor Set-up The Present Weather Sensor has between three to five connectors on its lower face. A typical configuration is specified in section 1.2.3, but the number and position of the connectors may vary depending on the exact configuration purchased. The cables provided will only fit the appropriate connectors on the sensor.
  • Page 38 Section 1 Sensor Set-up (3) System Interconnections: Eliminate all isolated ground loops. The shield of the signal output cable, for example, should be attached only at one end of the cable and left floating at the other end. Preferably, it should be attached to ground at the sensor end of the signal cable.

  • Page 39: Step 6 - Test And Commissioning

    1. Connect the power-input cable to a local power source, do not turn power source 2. Connect the signal cable to a PC running the Biral Sensor Interface Software. If this is not available, use a terminal program - for example Windows®...
  • Page 40 Parity ............None Flow Control ..........None 4. Turn the local power source "ON". If communications are working the sensor will respond with “Biral Sensor Startup”. 5. Check Data Transmission To Sensor. Send the command R? from the PC terminal to the sensor.

  • Page 41: Table 1-8 Remote Self-Test And Monitoring Message Fields

    Table 1-8 Remote Self-Test and Monitoring Message Fields 1.6.4 Calibration Check The sensor is fully calibrated before it leaves Biral. However, if you would like to carry out a user confidence calibration check please follow the calibration check procedure in section 5.2 to ensure that the MOR value changes i.e. the sensor responds to changes in visibility.
  • Page 42 Section 1 Sensor Set-up 1.6.5 Test Command If you wish to test the connections to the serial outputs of the sensor, use the TEST command. This command allows the sensor to be set to a known condition for a set period of time allowing the unit to temporarily simulate foggy and clear conditions, which will allow checking of the sensor and overall system performance.
  • Page 43 Section 1 Sensor Set-up Example: TEST,02,07.50,0,0,00 – Outputs a visibility of 7.5 km for 2 min (Clear conditions) TEST,06,00.10,0,0,30 – Outputs a visibility of 0.1 km for 6 min (Foggy conditions) Command Operation Where trailing fields of the TEST command are omitted they will be automatically substituted by the value zero.
  • Page 44 Section 1 Sensor Set-up CONGRATULATIONS YOUR SENSOR SHOULD NOW BE FULLY CONFIGURED, TESTED AND INSTALLED READY FOR USE THE REMAINDER OF THIS MANUAL COVERS: STANDARD DATA MESSAGES COMMANDS AND RESPONSES OPERATIONAL AND MAINTENANCE PROCEDURES CALIBRATION CHECK AND RE-CALIBRATION PROCEDURE MEASUREMENT PRINCIPLES SENSOR DETAILS AND SPECIFICATIONS STEP 6 –...

  • Page 45: Standard Operating Data

    Section 2 Standard Operating Data 2 STANDARD OPERATING DATA When in standard mode a data message will be output from the sensor every measurement period (default 60 seconds). When in polled mode the same message is output only in response to the D? command. The operating mode is checked by sending command “OSAM?”.

  • Page 46: Data Output Message Vpf-710

    Section 2 Standard Operating Data 2.1 Data Output Message VPF-710 2.1.1 VPF-710 Compressed Data Message The data message format is: <Date>,<Time>,CPaa,bbb.bb,ccc<cs>crlf Note: < > denotes an optional field. Message Meaning <Date> Optional Date string in the form DD/MM/YY. <Time> Optional Time string in the form HH:MM:SS. Compressed message header.
  • Page 47 Section 2 Standard Operating Data Typical compressed data messages from a VPF-710 are as follows: Default Configuration or EXCO field set to TEXCO. PEn set to 0 or 1, see section 1.4.12. CP01,000.12,OOO EXCO field replaced with MOR expressed in kilometres to two decimal places. PEn set to 2, see section 1.4.12.

  • Page 48: Table 2-2 Vpf-710 Expanded Data Message

    Section 2 Standard Operating Data Message Meaning c c c Self-Test and Monitoring (see section 4.2). c c c O = Other self-test values OK. X = Other self-test faults exist. O = Windows not contaminated. X = Window contamination warning – cleaning recommended. F = Window contamination fault –...
  • Page 49 Section 2 Standard Operating Data Typical expanded data messages from a VPF-710 are as follows: Default Configuration or EXCO field set to TEXCO. PEn set to 0 or 1, see section 1.4.12. VS01,000.55,XOO,100000,2.510,00.82,100,00,100,00,4040,+002.5,0000 EXCO field replaced with MOR expressed in kilometres to two decimal places. PEn set to 2, see section 1.4.12.

  • Page 50: Data Output Message Vpf-730

    Section 2 Standard Operating Data 2.2 Data Output Message VPF-730 2.2.1 VPF-730 Compressed Data Message The data message format is: <Date>,<Time>,CPaa,bb,ccc.cc,dd.dddd,±eee.e,fff<cs>crlf Note: < > denotes an optional field. Message Meaning <Date> Optional Date string in the form DD/MM/YY. <Time> Optional Time string in the form HH:MM:SS. Compressed message header.

  • Page 51: Table 2-3 Vpf-730 Compressed Data Message

    Section 2 Standard Operating Data Message Meaning f f f Self-Test and Monitoring (see section 4.2). f f f O = Other self-test values OK. X = Other self-test faults exist. O = Windows not contaminated. X = Window contamination warning – cleaning recommended. F = Window contamination fault –...
  • Page 52 Section 2 Standard Operating Data 2.2.2 VPF-730 Expanded Data Message The data message format is: <Date>,<Time>,PWaa,bbbb,cccc,ddd.dd KM,eee,ff,gg.gg,hh.hhhh,±iii.i C,jjjj,kkk.kk,lll.ll,mmm.mm, nnnn,ooo,ppp,qqq.qq<cs>crlf Note: < > denotes an optional field. Message Meaning <Date> Optional Date string in the form DD/MM/YY. <Time> Optional Time string in the form HH:MM:SS. Present Weather message header.

  • Page 53: Table 2-4 Vpf-730 Expanded Data Message

    Section 2 Standard Operating Data Message Meaning gg.gg Receiver background illumination. hh.hhhh Amount of water in precipitation in last measurement period (mm). ±iii.i C Temperature (ºC). jjjj Number of precipitation particles detected in last measurement period. kkk.kk Transmissometer equivalent EXCO (km lll.ll EXCO less precipitation particle component (km ±mmm.mm...
  • Page 54 Section 2 Standard Operating Data Typical expanded data messages from a VPF-730 are as follows: EXCO output configuration: PEn command not applicable to the VPF-730 expanded output message as both EXCO and TEXCO provided. MOR in default configuration, see section 1.4.11. PW01,0060,0000,000.42 KM,NP ,FG,00.41,00.0000,+013.0 C,0000,007.12, 007.12,+026.17, 0001,000,OOO,007.12 MOR output in metres, see section 1.4.11 .

  • Page 55: Data Message Variations For Als Or Wsm (Vpf-710 And Vpf-730)

    Section 2 Standard Operating Data 2.3 Data Message Variations For ALS or WSM (VPF-710 and VPF-730) For sensors fitted with an Ambient Light Sensor or Weather Station Module, data output strings are identical to the standard message with the following appended to the message prior to the optional check sum<cs>...

  • Page 56: Data Output Message Vpf-750

    Section 2 Standard Operating Data 2.4 Data Output Message VPF-750 2.4.1 VPF-750 Compressed Data Message The data message format is: <Date>,<Time>,CP,nnn,ww,aa.aa KM,bb.bbbb,±ccc.c,ddd,+eeeee,fff<cs>crlf Note: < > denotes an optional field. Message Meaning <Date> Optional Date string in the form DD/MM/YY. <Time> Optional Time string in the form HH:MM:SS.
  • Page 57 Section 2 Standard Operating Data Message Meaning Moderate Drizzle Heavy Drizzle Freezing Slight Drizzle Freezing Moderate Drizzle Freezing Heavy Drizzle Slight Drizzle and Rain Moderate or Heavy Drizzle and Rain Slight Rain Moderate Rain Heavy Rain Freezing Slight Rain Freezing Moderate Rain Freezing Heavy Rain Slight Rain and Snow Moderate or Heavy Rain and Snow...

  • Page 58: Table 2-7 Vpf-750 Compressed Data Message

    Section 2 Standard Operating Data Message Meaning d d d Self-Test and Monitoring (see section 4.2). O = Other self-test values OK X = Other self-test fault exists F = Forward Scatter Receiver Flooded with Light B = Backscatter Receiver Flooded with Light T = Temperature / Humidity sensor Fault O = Windows not contaminated X = Windows contaminated –...
  • Page 59 Section 2 Standard Operating Data Typical compressed data messages from a VPF-750 are as follows: EXCO output configuration: PEn command not applicable to the VPF-750 compressed output message as no EXCO field provided. MOR in default configuration, see section 1.4.11. CP,001,52,09.30 KM,00.0426,+008.6,OOO,+00071,OOO MOR output in metres, see section 1.4.11 .
  • Page 60 Section 2 Standard Operating Data 2.4.2 VPF-750 Expanded Data Message The data message format is: <Date>,<Time>,VPF750,nnn,xxxx,aa.aa KM,cc, w ,dd,eeeee,fff.fff,gg.gg KM, hhh.hh,±iii.ii,jjj.j C,kkk %,lll,±mmmmm,nnn,oo.oooo,ppp<cs>crlf Note: < > denotes an optional field. Message Meaning Optional Date string in the form DD/MM/YY. <Date> Optional Time string in the form HH:MM:SS.
  • Page 61 Section 2 Standard Operating Data Message Meaning Indeterminate precipitation type Slight Drizzle Moderate Drizzle Heavy Drizzle Freezing Slight Drizzle Freezing Moderate Drizzle Freezing Heavy Drizzle Slight Drizzle and Rain Moderate or Heavy Drizzle and Rain Slight Rain Moderate Rain Heavy Rain Freezing Slight Rain Freezing Moderate Rain Freezing Heavy Rain...
  • Page 62 Section 2 Standard Operating Data Message Meaning Past Weather Type2 SYNOP Code: No past weather code Fog or Thick Haze Drizzle Rain Snow or Mixed rain & snow Showers Obstruction to Vision Message: (Blank) No obstruction Haze Dust Smoke Mist eeeee METAR Reporting Code.

  • Page 63: Table 2-8 Vpf-750 Expanded Data Message

    Section 2 Standard Operating Data Message Meaning ALS Self-Test and Monitoring (see section 4.2). FFF if ALS-2 not connected O = Other self-test values OK X = Other self-test fault exists O = Window not contaminated X = Window contaminated – cleaning recommended/required F = Window contaminated –...
  • Page 64 Section 2 Standard Operating Data 2.4.3 METAR Codes Code METAR Description Number Code Not Ready (first 5 minutes from restart) No significant weather observed, or sensor starting Haze, visibility greater than or equal to 1KM smoke, visibility greater than or equal to 1KM Dust, visibility greater than or equal to 1KM Mist Diamond Dust...

  • Page 65: Table 2-9 Metar Codes

    Section 2 Standard Operating Data Code METAR Description Number Code -RADZ Drizzle and Rain, slight RADZ Drizzle and Rain, moderate +RADZ Drizzle and Rain, heavy Rain, not freezing, slight Rain, not freezing, moderate Rain, not freezing, heavy -FZRA Rain, freezing, slight FZRA Rain, freezing, moderate +FZRA...
  • Page 66 Section 2 Standard Operating Data 2.4.4 VPF-750 WMO 4680 and METAR Codes The VPF-750 reports weather phenomena using both WMO Table 4680 and METAR codes. As there is not always a METAR code associated with the WMO Table code the following logic is used to determine what codes to report.

  • Page 67: Commands And Responses

    Section 3 Commands and Responses 3 COMMANDS AND RESPONSES 3.1 Sensor Commands All commands should be terminated with <Carriage Return> and <Line Feed> <crlf>, (see Section 1.3). Commands marked with * cause the sensor to reset. Commands marked with must be preceded by the calibration enable command CO. Command Function Response...
  • Page 68 Section 3 Commands and Responses Command Function Response 710 730 750 Set sensor identification number displayed in data message. IDx* √ √ √ 710/730 Range x = 0 to 99. (Default = 1). Range x = 0 to 999. (Default = 1). See Section Query current MOR output resolution.

  • Page 69: Table 3-1 Commands For Vpf-700 Series Of Sensors

    Section 3 Commands and Responses Command Function Response 710 730 750 Query program version message. √ √ √ SIxxxxxx.yyy Send remote self-test and monitoring See Section √ √ √ message. 3.1.2 RST* Restart sensor. √ √ √ See Section Query sensor times message. √...
  • Page 70 Section 3 Commands and Responses 3.1.1 Commands A? and AC – Precipitation Accumulation These commands apply only to the VPF-730 and VPF-750. The sensor records the total amount of precipitation detected in a 24-hour period. The 24-hour period starts when the sensor is powered or when the accumulated precipitation value is reset.

  • Page 71: Table 3-2 Command R? Response

    Section 3 Commands and Responses 3.1.2 Command R? - Send Remote Self-Test and Monitoring Message Example response: _100,2.509,24.1,12.3,5.01,12.5,00.00,00.00,100,105,107,00,00,00,+021.0 ,4063 Field Range / Value Description Field 1: Space The message starts with a space. Field 2: Heater state and error flags. A = 1 - Window heaters ON.

  • Page 72: Figure 6-3 Precipitation Matrix

    Section 3 Commands and Responses 3.1.3 Command M? – Send Precipitation message This command is only available for the VPF-730 and VPF-750. The sensor responds by sending a precipitation matrix accumulated over the last five measurement periods. This is a matrix of 16 rows with up to 21 readings, each being the number of precipitation particles of that specific size and velocity.
  • Page 73 Section 3 Commands and Responses 3.1.4 Command T? - Send Sensor Times Message Response: aaaa,bbbb,ccccc,dddd aaaa: Measurement interval for each operational data message (10 to 300 seconds) (default = 60). bbbb: Auxiliary measurement sample period - time between measurement of peripheral signals during measurement interval.

  • Page 74: Sensor Responses

    Section 3 Commands and Responses 3.2 Sensor Responses Response Meaning Your command was not understood by the sensor. Check the text BAD CMD of the command and re-send. An error was detected in a character in the command. Re-send COMM ERR the command.

  • Page 75: Maintenance Procedures

    Section 4 Maintenance Procedures 4 MAINTENANCE PROCEDURES The VPF-700 series of sensors require very little maintenance. The following sections detail the checks that are advisable to ensure continued good operation of the sensor. The frequency of these checks depends upon the location and environmental conditions under which the sensor operates.
  • Page 76 PC running a terminal program such as the Biral Sensor Interface Software, or HyperTerminal™. The heaters may be switched on temporarily using the command DHO and off again using the command DHX. The default setting is ON with automatic control.

  • Page 77: Self-Test Codes

    Section 4 Maintenance Procedures 4.2 Self-Test Codes Self-Test and Monitoring information is provided in all standard Operating Data Messages, both of compressed and expanded formats. This information consists of three alpha-numeric characters which have the following meanings. Note: The command “R?” provides a response with full diagnostic information. The extent of this information depends on the sensor configuration specified at time of purchase.
  • Page 78 Section 4 Maintenance Procedures deteriorate as the contamination increases. The windows require cleaning. The values of WT and WF can be queried and set using the WT and WF commands as described in section 3.1. Note: The ALS has an additional code of “S”. This indicates that the sensor is saturated with a VERY bright light source (such as direct view of the sun).
  • Page 79 Section 4 Maintenance Procedures sensor with either this fault present or the temperature and humidity sensor disconnected. It will also detect the presence of precipitation correctly, but may provide incorrect precipitation type indications. Self-Test Codes...

  • Page 80: User Confidence Checks

    Maintenance Procedures 4.3 User Confidence Checks The following user confidence checks require bi-directional communications with a PC running the Biral Sensor Interface Software. If this is not available, use a terminal program - for example Windows HyperTerminal™. 4.3.1 EXCO Calibration Check If you wish to carry out a user confidence calibration check please follow the calibration check procedure in section 5.2 to ensure that the Exco value changes i.e.
  • Page 81 Section 4 Maintenance Procedures 4.3.3 Window Monitor Checks The VPF-700 series of sensors all monitor the contamination of the transmitter window. Monitoring of the receiver windows is standard for the VPF-750 and a factory fitted option for the VPF-710 and VPF-730. The values measured are used to adjust the EXCO value, and are also used to determine when the windows should be cleaned.
  • Page 82 Section 4 Maintenance Procedures Step 5. Insert a piece of white card or paper in the forward scatter receiver hood so that it blocks the window, and almost touches it. Step 6. Wait for operational data message from the sensor. Step 7.
  • Page 83 Section 4 Maintenance Procedures Step 4. Remove the zero plugs from the Sensor Head receiver hood. Step 5. While shining a flashlight directly into the receiver window send the command: R? Note: This test requires the use of a filament bulb flashlight. There is insufficient IR radiation from a visible LED source.

  • Page 84: Calibration Procedures

    Section5 Calibration Procedures 5 CALIBRATION PROCEDURES This section explains how to CHECK the calibration of the sensor and ONLY IF NECESSARY how to recalibrate it. ALL THE PROCEDURES IN THIS SECTION REQUIRE A VPF-700 SERIES CALIBRATION KIT ENSURE THE CORRECT MODEL AND REVISION OF CALIBRATION KIT IS AVAILABLE.
  • Page 85 Section5 Calibration Procedures incompatible Calibration Kit may result in damage to the sensor and Calibration Kit. The carry case of the VPF Calibration Kit is fitted with a label stating, “VPF Calibration Plaque” or “VPF.CAL”. In January of 2014 the main IRED light source of the VPF-700 sensor family was changed from a device operating at 880nm to one operating at 850nm;...

  • Page 86: Calibration Check

    The following instructions show you how to check the calibration of a VPF-700 series sensor. This procedure can only be completed with: A VPF-700 Series Calibration Kit. Connection to a PC running the Biral Sensor Interface Software, or, if this is not available, terminal emulation software (such as Windows ® . If you HyperTerminal™).

  • Page 87: Figure 5-1 Assembly Of Calibration Reference Plaque

    Section5 Calibration Procedures Calibration Reference Plaque Calibration arm Figure 5-1 Assembly of Calibration Reference Plaque (Example of calibration plaque in-situ on VPF-730) Step 1: Clean all windows on the sensor using a dilute detergent solution or pure alcohol (propanol) and soft cloth or tissue, preferably lens tissue. Check the cleanliness using a portable light if possible.
  • Page 88 Section5 Calibration Procedures Step 8: Remove the foam plugs. EXCO gain Check: Step 9: Send the command “RST” to restart the sensor. Verify the response is “OK”. Step 10: If the sensor is operating in the polled mode, send “D?” command at 60 seconds intervals.

  • Page 89: Sensor Re-Calibration

    Section5 Calibration Procedures 5.3 Sensor Re-Calibration RE-CALIBRATING THE EXTINCTION COEFFICIENT SHOULD ONLY BE CARRIED OUT IF THE SENSOR HAS FAILED A CORRECTLY PERFORMED USER CONFIDENCE CHECK WARNING ERRORS DURING THIS RE- CALIBRATION PROCEDURE WILL CAUSE THE SENSOR TO GIVE INCORRECT DATA BEFORE CONTINUING ENSURE THAT: 1.
  • Page 90 Section5 Calibration Procedures BLOCK TRANSMITTER OPTICS, (not for VPF-710), BLOCK BK SCAT RCVR OPTICS, INSTALL REF STD, ENTER FWD SCAT EXCO (/KM) FORM: XXX.XX Step 4. Ensure that the windows are clean. Fit the three foam plugs (supplied with the calibration kit) against the windows (only 2 used for the VPF- 710).

  • Page 91: Temperature Calibration (Not Vpf-750)

    Calibration Procedures are outside these limits carefully repeat the calibration procedure. If the limits are again exceeded contact Biral. Step 13. Remove the calibration reference plaque assembly from the sensor, dismantle it and return it to its protective case for storage.
  • Page 92 Section5 Calibration Procedures Value entered = __ Desired precipitation accumulation * 100 Sensor's reported precipitation accumulation EXAMPLE: Over several rainstorms, a reference sensor measures an accumulation of 225 millimetres. The sensor reported an accumulation of 244 millimetres. To adjust the sensor's precipitation accumulation factor, the value to be entered is: 225 x 100 = 92.2 The procedure to be used for precipitation amount calibration is as follows: Step 1.

  • Page 93: Measurement Principles

    Section 6 Measurement Principles 6 MEASUREMENT PRINCIPLES 6.1 Visibility Measurement Terminology The VPF-700 Sensor of Series has all the capabilities of a forward scatter meter (FSM); i.e. it belongs to the class of nephelometers which measure the amount of light scattered at angles less than 90 degrees by small particulates suspended in, or large particles passing through its sample volume.

  • Page 94: Figure 6-2 Effects Of Atmosphere On Perceived Brightness Of Target Objects

    Section 6 Measurement Principles Koschmieder's Law (for daytime visual range), Allard's Law (for night-time visual range), or Variations on Koschmieder and Allard's Laws. When an observer looks at a distant target the light from the target that reaches the observer is diminished by absorption and scattering (the two components of extinction).
  • Page 95 Section 6 Measurement Principles Where  is the atmospheric extinction coefficient. Subsequent investigations concluded that Koschmieder used too optimistic a value (0.02) for the liminal contrast threshold value of the human eye. A liminal value of 0.05 is believed to be more realistic. For the latter contrast threshold Koschmieder's Law is modified to become: ...

  • Page 96: Extinction Coefficient Calibration

    Aviation Organisation document 9328 – Manual of Runway Visual Range Observing and Reporting Practices. A Primary Scatter Meter Calibration Unit (SCU) or calibration plaque was produced as part of the calibration exercise. Secondary calibration plaques are used to calibrate all Biral visibility and present weather sensors. Visual Range Determination...

  • Page 97: Theory Of Forward Scatter Meters

    Section 6 Measurement Principles 6.4 Theory of Forward Scatter Meters 6.4.1 Optical Sensor Configuration The visibility measurement capability of the VPF-700 series of sensors derives from its forward scatter meter (FSM) configuration. Unlike a transmissometer, which measures the total atmospheric extinction coefficient, a FSM measures only an angular portion of the atmospheric scattering coefficient, that is, the scattering in a narrow range of angles around a central forward scatter angle.
  • Page 98 Section 6 Measurement Principles 6.4.2 Visibility in Fog & Haze The angular scattering coefficient can be separated into two components, a phase function  () and the total scattering coefficient  as follows:      To replace the total scattering coefficient by the angular scattering coefficient, as required for valid measurements with a FSM, it is obvious that the phase function must be a constant for all environmental conditions in which visibility measurements are of interest (usually all weather conditions).
  • Page 99 Section 6 Measurement Principles from 50 meters to 2000 meters. This range encompasses only two environmental conditions, fog and very heavy haze. To assure that the fog calibration of VPF sensors remains valid for lighter haze conditions and clear air, extensive use has been made of visual observations and televisiometer measurements.
  • Page 100 6.4.4 Transmissometer Equivalent EXCO A BIRAL present weather sensor can satisfy either school of opinion using its unique measurement techniques. For those that believe that the FSM measurements characterise the true extinction coefficient in rain, the total EXCO value normally provided by the sensors is always available.
  • Page 101 1.0 micron and for visibilities extending to 100 kilometres. BIRAL FSMs operate at a wavelength of 0.85 microns because of the high powered IREDs available at that wavelength compared with LED's operating in the visible spectral region at the peak of the eye response (0.55 microns).
  • Page 102 Section 6 Measurement Principles Atmospheric aerosol models show, in addition to the wavelength dependence, a slight wavelength dependence of the phase functions as well. For the two wavelengths of interest in the above example, the phase functions in fog and haze are as follows: ...

  • Page 103: Precipitation Measurements

    Section 6 Measurement Principles 6.5 Precipitation Measurements An automated present weather sensor must be capable of determining the type, intensity and quantity of precipitation in addition to the visibility. In the case of the VPF-700 series of sensors these precipitation parameters are established by a combination of several methods.
  • Page 104 Section 6 Measurement Principles Matrix. The "Signature" is the particle size/velocity distribution that is characteristic of each type of precipitation phenomena. An example of a precipitation recognition matrix is shown in Figure 6-3 Precipitation Matrix. This figure portrays a 16 x 21-matrix array of particle sizes and velocities. Sizes are arranged in columns and velocities in rows.
  • Page 105 Section 6 Measurement Principles components housed in the power/control system are shown enclosed in the other dashed line. When a particle of precipitation passes through the sample volume, light from the LED source, which is housed in the transmitter section of the sensor head, is scattered into the receiver section where it is sensed by the photo detector.
  • Page 106 Section 6 Measurement Principles Figure 6-3 Precipitation Matrix Precipitation Measurements...

  • Page 107: Figure 6-4 Vpf-700 Sensor Functional Block Diagram

    Section 6 Measurement Principles Figure 6-4 VPF-700 Sensor Functional Block Diagram. Precipitation Measurements...

  • Page 108: Product Overview

    Section 7 Product Overview 7 PRODUCT OVERVIEW 7.1 VPF-700 Series of Present Weather Sensors 7.1.1 Available Sensor Models There are three models in the VPF-700 series of present weather sensors, the VPF- 710, the VPF-730 and the VPF-750. They use the same basic opto-mechanical and electronic components and have an optical transmitter and forward scatter receiver.
  • Page 109 Section 7 Product Overview VPF-750 Visibility Precipitation type identification This model has an extra precipitation sensor and an extra high accuracy temperature and humidity sensor for: 50 weather codes (from WMO Code Table 4680), including: Past Weather Freezing Rain Ice Pellets 7.1.2 Sensor Components Each sensor has been engineered and manufactured with high-reliability components to provide accurate measurements under all weather conditions.
  • Page 110 Section 7 Product Overview 7.1.3 Optional Items Hood Heaters Heaters for the transmitter and receiver hoods. These are to minimise any build-up of ice within the optical paths. They consist of 15W heaters per hood on all versions. Advanced Self-Test and Monitoring In addition to the standard self-test transmitter window monitoring the sensors can have the optional receiver window monitoring to provide warning of additional contamination build-up.

  • Page 111: Sensor Features

    Section 7 Product Overview Transit Case A rigid re-usable transit case designed to provide full protection to the sensor for regular shipping is available. Mains Adapter A mains adapter is available if required. Ambient Light Sensor An ambient light sensor can be supplied as part of the VPF-700 system. This provides measurements of the ambient light intensity up to 40,000 Cd/m , with its output integrated into the standard VPF-700 data output string.
  • Page 112 The ASCII text data message is easy to interface to a wide range of hardware and software. The message can also be directly interpreted using the Biral Sensor Interface Software or a terminal emulation program for test and debugging purposes: 1.

  • Page 113: Present Weather Measurements

    Section 7 Product Overview 7.3 Present Weather Measurements 7.3.1 Present Weather Definition The term "Present Weather" is generally employed to define a large class of atmospheric phenomena that includes tornado activity, thunderstorm activity, precipitation, obstructions to vision, and "other atmospheric phenomena" such as aurora.

  • Page 114: Table 7-1 Visibility Measurement Specification

    Section 7 Product Overview of EXCO-EVENTS is greater than 3.00, then fog is declared to be present in addition to the precipitation as an obstruction to vision. Visibility Measurements Function Details Meteorological Optical 10 metres to 75km (30 feet to 46 miles) Range Atmospheric Extinction 300km...

  • Page 115: Table 7-3 Additional Measurement Capabilities Vpf-750

    Section 7 Product Overview Additional Precipitation/Obstruction to Vision Measurements (VPF-750) Function Details Identification/Intensity Drizzle and Rain: Slight/Moderate/Heavy Non-Freezing Freezing Fog Freezing Drizzle Slight/Moderate/Heavy Freezing Rain Slight/Moderate/Heavy Rain (Drizzle) and Snow Slight/Moderate/Heavy Identification/Intensity Ice Pellets Slight/Moderate/Heavy Freezing Diamond Dust Blowing or Drifting Snow Snow Grains Ice Crystals Hail / Small Hail...
  • Page 116 Section 7 Product Overview 7.3.4 Precipitation Measurements The VPF-730 and VPF-750 sensors identify three forms of precipitation, namely drizzle, rain and snow together with a wide variety of frozen forms of these (VPF-750 only). Detection of the onset of precipitation is extremely sensitive, being 0.00025 mm per minute for rain and approximately 0.000025 water equivalent mm per minute for snow.
  • Page 117 Section 7 Product Overview 7.3.5 Reported Precipitation Codes The following present weather codes, from WMO Table 4680 are used on the VPF-700 series of sensors: VPF-710 – Visibility only, no weather codes VPF-730 – Compressed message only: No significant weather observed, or not ready Haze or Smoke or Dust Mist (If optional high accuracy temperature / humidity sensor fitted) Indeterminate precipitation type...
  • Page 118 Section 7 Product Overview Fog becoming thinner in last hour Fog no appreciable change in last hour Fog begun or becoming thicker in last hour Freezing Fog Indeterminate precipitation type Slight Drizzle Moderate Drizzle Heavy Drizzle Freezing Slight Drizzle Freezing Moderate Drizzle Freezing Heavy Drizzle Drizzle and Rain, Slight Drizzle and Rain, Moderate or Heavy...

  • Page 119: Sensor Specifications

    Section 7 Product Overview 7.4 Sensor Specifications The specifications for all versions of the VPF-700 series of sensors are summarised in the following pages. To adapt the table to a particular sensor model, disregard non- pertinent information. For example, in the case of the Model VPF-710 visibility sensor, disregard those portions of the specification pertaining to precipitation measurements.

  • Page 120: Table 7-5 Sensor Specifications

    Section 7 Product Overview Maintenance Function Details MTBF (Calculated) 52,500 hrs (6 years) Calibration Check 6 months recommended 3 months recommended, dependent on Clean Windows environment Remote Self-Test Monitoring Included VPF-750 Specific Temperature and Humidity Measurements Function Details Humidity: Type Capacitive Range 0 to 100% Relative Humidity...
  • Page 121 Section 7 Product Overview 7.4.1 Sensor Characteristics Physical Function Details Scattering Angle Coverage 39 to 51 Sample Volume 400 cm Weight VPF-710 DC Sensors 4.9kg Mains Powered Sensors 6.1kg VPF-730 DC Sensors 5.6Kg Mains Powered Sensors 6.8Kg VPF-750 DC Only 7.4kg Length 0.75 m...

  • Page 122: Table 7-6 Sensor Characteristics

    Section 7 Product Overview Power Requirements Function Details Basic Sensor 3.5 W VPF-710: 30W (17W for 12V DC Version) De-Icing Heaters VPF-730: 45W (25W for 12V DC (Optional) Version) VPF-750: 45W VPF-710: 1.7 W No-Dew Window Heaters VPF-730 and VPF-750: 2.5 W VPF-750 Additional Sensors: Precipitation Sensor 0.2W...

  • Page 123: Table 7-7 Digital Communication Interface Specifications

    Section 7 Product Overview 7.4.2 Digital Communication Interface Communication Protocols Function Details Interface Type RS232C, (Full Duplex) Optional RS422 or RS485 Parameters: Function Details Baud Rates 1200 Baud to 57K6 Baud, selectable Data Bits Parity None Stop Bits Flow Control None Message Termination CR-LF...
  • Page 124 Section 7 Product Overview 7.4.3 Sensor Remote Self-Test Capabilities Standard Self-Test and Monitoring • Optical Source Power • Transmitter Window Contamination • Power Supply Voltages • Non-Volatile Memory Check Sum Test • EPROM Check-Sum Test • Restart Occurrence • Sensor Sample Interrupt Verification •...
  • Page 125 Section 7 Product Overview Standard Self-Test and Monitoring is a Standard Feature on the VPF-710 and VPF- 730 sensors. Advanced Self-Test and Monitoring is an Optional Accessory on the VPF-710 and VPF-730 sensors. Advanced selftest is a standard feature of the VPF-750 Sensor Specifications...

  • Page 126: Series Of Sensors - Dimensions

    Section 7 Product Overview 7.5 VPF-700 Series of Sensors - Dimensions The model shown is the VPF-730 (and VPF-750). The VPF-710 is identical except that the Backscatter Head is not fitted. Backscatter Head Figure 7-1 VPF-730 Model Dimensions (mm) (VPF-750) is identical) VPF700 Dimensions...

  • Page 127: Index

    Section 8 Index 8 INDEX Ambient Light Sensor ......................102 CCESSORIES Calibration Kit .......................... 101 High Accuracy Temperature and Humidity Sensor ................102 Mains Adapter ............................102 Transit Case ............................102 FTER ALES UPPORT ............................MBIENT IGHT ENSOR ......................3, 26, 27, 46, 102 ACKSCATTER ECEIVER .....................
  • Page 128 Section 8 Index EXCO Output Configuration ........................21 MOR Output Resolution ..........................20 RS485 ................................ 14 ONTACT ETAILS .............................. ESSAGES ............................... 36 Variations for ALS or WSM ........................46 VPF710 ..............................37 VPF730 ..............................41 VPF750 ..............................47 ............................ 11 ATE AND TAMP ..........................
  • Page 129 Section 8 Index Siting Considerations ..........................22 VPF750 Assembly ............................. 27 IP R ATING ..............................113 AINS DAPTER ..............................3 AINTENANCE User Confidence Checks Receiver Background Brightness Check ..................73 ........................66–74 AINTENANCE ROCEDURES General Checks ............................66 Hood Heaters ............................66 Window Cleaning ..........................
  • Page 130 Section 8 Index Transit Case ............................... 3 Weather Station Module ........................... 3 RIENTATION NSTALLATION ..........................(VPF750) ......................... 106 EATHER ............................7 OWER ONNECTIONS ........................61 RECIPITATION CCUMULATION RECIPITATION MOUNT ALIBRATION ....................... 82 ........................94 RECIPITATION DENTIFICATION ......................107, 110 RECIPITATION EASUREMENTS ............................
  • Page 131 Section 8 Index ............................117 ENSOR IMENSIONS ENSOR EATURES ............................102 ............................65 ENSOR ESPONSES ............................6 IGNAL ONNECTIONS ) ..........3, 43, 70 EMPERATURE AND UMIDITY ENSOR XTERNAL CCURACY EMPERATURE ALIBRATION ..........................82 .......................... 8, 30 EST AND OMMISSIONING TAMP ..............................

  • Page 132: Notes

    Section 9 Notes 9 NOTES: Notes...

This manual is also suitable for:

Vpf-710Vpf-730Vpf-750

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