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Campbell CS120A, Instruction Manual

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Campbell CS120A Instruction Manual Download Page 72

CS120A and CS125 Visibility and Present Weather Sensors 

60 

 

5.

 

After the bags of desiccant have been allowed to cool in an airtight desiccator, 
they may be removed and placed in either an appropriate type polyliner 
tightly sealed to prevent moisture adsorption, or a container that prevents 
moisture from coming into contact with the regenerated desiccant. Some care 
should be taken when re-activating desiccant bags. If heated in an oven which 
is too hot, the bags may burst. If in any doubt, we recommend purchasing 
new desiccant packs instead of oven drying. Failure to use or exchange the 
desiccant may lead to condensation inside the enclosure. Not only will this 
lead to corrupted data but, in the long term, can also cause corrosion which is 
expensive to repair. 

 

 

Summary of Contents for CS120A

Page 1: ...CS120A and CS125 Visibility and Present Weather Sensors Issued 6 11 17 Copyright 2013 2017 Campbell Scientific Ltd CSL 1141 INSTRUCTION MANUAL ...

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Page 3: ...s under guarantee or not Please state the faults as clearly as possible and if the product is out of the guarantee period it should be accompanied by a purchase order Quotations for repairs can be given on request It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment in support of this policy a Declaration of Hazardous Material and De...

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Page 5: ...nt for recycling Any batteries contained within the product or used during the products life should be removed from the product and also be sent to an appropriate recycling facility Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases arrange collection and the correct disposal of it although charges may apply for some items or territories For further advice or su...

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Page 7: ...fore beginning work Wear a hardhat and eye protection and take other appropriate safety precautions while working on or around tripods and towers Do not climb tripods or towers at any time and prohibit climbing by other persons Take reasonable precautions to secure tripod and tower sites from trespassers Use only manufacturer recommended parts materials and tools Utility and Electrical You can be ...

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Page 9: ...cation 6 3 2 Optical specification 7 4 Communications specification 8 4 1 Communications electrical specifications 8 4 2 Supported data rates and formats 8 5 Environmental specifications 9 6 Mechanical specifications 10 6 1 Dimensions 10 6 2 Weights 10 6 3 Mounting 10 7 Installation procedure 10 7 1 Equipment grounding 12 7 2 Mounting the sensor 12 7 3 Optional Campbell Scientific Mount 15 8 Senso...

Page 10: ...sensor 35 13 Definition of the variables that can be set by the user on the sensor 35 14 Command line mode 37 14 1 The SET Command 37 14 1 1 Example of a SET Command 38 14 2 The SETNC Command 38 14 2 1 Example of a SETNC Command 39 14 3 The MSGSET Command 39 14 4 The GET Command 41 14 5 The MSGGET Command 44 14 6 The POLL Command Polling the sensor 45 14 7 The ACCRES Command Resetting the accumula...

Page 11: ...ed map used by the CS125 present weather algorithm 5 7 1 Airflow 11 7 2 Grounding boss 12 7 3 Mounting arrangement 13 7 4 Mounting to a flat surface 14 7 5 Use of band clamps 14 7 6 Optical sensor mast 15 7 7 Mounting footprint 16 8 1 Connections 17 8 2 Communications and power connections 19 8 3 Communications and power connector 20 8 4 Configuration cable 20 8 5 USB configuration cable 20 9 1 Co...

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Page 13: ...t based stations They both use the well established forward scatter system for visibility measurement utilising a 42º scatter angle The CS125 uses high speed sampling to reduce missed events and improves response to other suddenly changing conditions The CS125 has a temperature sensor mounted in the cross arm used as part of the process for identifying precipitation When an optional CS215 temperat...

Page 14: ...ight useful information in the installation use and maintenance of this product These should be followed carefully in order to gain the maximum benefit from the use of this product 1 2 Sensor Unit Safety The sensor has been checked for safety before leaving the factory and contains no internally replaceable or modifiable parts Do not modify the sensor unit Such modifications will lead to damage of...

Page 15: ...tion of the emitted beam caused by scattering The scattering signal averaged over one second is used to calculate an extinction coefficient or EXCO Sixty one second averages are then themselves averaged to give a one minute average EXCO This is then converted to a value of Meteorological Optical Range MOR using Koschmieder s law MOR 3 EXCO where MOR is in km and EXCO in units of km 1 The CS125 is ...

Page 16: ...re and relative humidity probe is connected then a wet bulb temperature can be calculated This provides useful additional information identifying particles more accurately especially between liquid and frozen around 0 C Figure 1 3 shows how these temperatures are used to define possible precipitation types around 0 C Figure 1 3 Defining possible precipitation types based on wet bulb and dry bulb t...

Page 17: ...lt communication RS 232 8N1 38400 baud a sensor ID 0 and set to transmit default messages full format visibility only for the CS120A SYNOP present weather full format for the CS125 at 1 minute intevals see Section 11 To start using the CS120A or CS125 first connect a DC supply matching the specification in Section 3 1 to the red and black wires on the D connector see Figure 8 3 and connect to a PC...

Page 18: ...ly Reported accumulation range 0 999 9 mm Accumulation accuracy 20 Accumulation resolution 0 1 mm Reported intensity range 0 999 9 mm hr Intensity accuracy 20 Intensity resolution 0 1 mm Detection threshold for present weather 0 02 mm hr 3 Technical specification 3 1 Electrical specification Minimum Value Nominal Value Maximum Value Main power supply for DSP and dew heaters Power supply DC only 7V...

Page 19: ... 3 If hood heaters are not being used ensure Hood heater override details in Section 13 is set to off 4 It is recommended that the hood heaters are run at 24V AC DC It s possible to run the heaters at any voltage below 24V but the heaters will generate proportionally less heat reducing their ability to prevent ice build up 5 Each hood takes 30W 60W is the total for both hoods on the sensor togethe...

Page 20: ...s RS 485 input threshold voltage 0 2V 0 2V RS 485 output Unloaded 5V RS 485 output Load 50 2V Maximum voltage at any terminal 2 7V 7V 1 The RS 232 communications interface will automatically turn itself off when not transmitting 2 The ground of the sensor and the ground of any RS 485 equipment cannot be further apart than this voltage The sensor ground pin 1 on connector B see page 18 can be conne...

Page 21: ...alue Sensor temperature ranges Operating temperature 25 C 60 C Extended operating temperature 40 C 70 C 1 Storage temperature 40 C 85 C Sensor humidity ranges Operating humidity range 0 100 Sensor heater thresholds Dew heater Turn On 35 C Dew heater Turn Off 40 C Hood heater Turn On 15 C Hood heater Turn Off 25 C 1 Extended temperature ranges are only guaranteed if the sensor has been tested by Ca...

Page 22: ...or mounting Bracket mounts on a vertical pole 32 52 5 mm diameter The mounting bracket has cut outs for band clamps for larger diameter masts 7 Installation procedure The sensor measures environmental variables and is designed to be located in harsh weather conditions However there are a few considerations to take into account if accurate and representative data from a site are to be obtained ...

Page 23: ...is unrepresentative of the general speed and direction Eddies are generated in the lee of the windbreak and air is displaced upwind of it The height and depth of these affected zones varies with the height and to some extent the density of the obstacle Generally a structure disturbs the airflow in an upwind direction for a distance of about twice the height of the structure and in a downwind direc...

Page 24: ...be sufficient Otherwise the mounting bracket should be earthed and a grounding boss is supplied to allow this A ground wire with a minimum cross section of 6 mm2 and maximum length of 5 m should be used The pole and foundations of a pole mounted installation will provide some basic lightning protection and protection against radio frequency interference and should also be correctly grounded Figure...

Page 25: ...ensor is to be mounted onto another type of mast please refer to the manual for that mast for mounting details Ensure that the sensor is mounted according to the figure below Do not reposition once fixings are tightened by forcing the arms of the unit as this can cause damage Do not remove the mounting plate as this will compromise resistance to water ingress Figure 7 3 Mounting arrangement If you...

Page 26: ...d CS125 Visibility and Present Weather Sensors 14 Figure 7 4 Mounting to a flat surface Slots are provided to allow band clamps to be used with larger diameter masts see Figure 7 5 Figure 7 5 Use of band clamps ...

Page 27: ...truments and Methods of Observation 7th Edition Section 9 3 4 Figure 7 6 Optical sensor mast If one is to be used follow the installation instructions below The mount should be installed on a concrete foundation If one does not already exist then a concrete foundation should be constructed at least 600 mm square and 600 mm deep Ensure the ground consistency is not too loose and will be able to sup...

Page 28: ...rs supplied to protect the threads during installation Hammer the wedge anchors into the holes until the start of the threads are below the surface Tighten the nuts until about 25 mm of thread protrudes above the surface Remove the washers and nuts from the protruding length screw Then lower the mount into place Finally secure the mount with the washers and nuts If the surface is not level and fla...

Page 29: ...fitted this usually uses gland 4 If you need to run cables through the cable glands follow these guidelines If a torque wrench is available use a torque of 2 5 Nm do not over tighten Otherwise tighten with fingers as tight as possible and then add a further turn with a 19 mm spanner do not over tighten The glands are suitable for cables between 5 and 9 mm diameter If the power cable is incorrectly...

Page 30: ...Pin number Description Notes Pin 1 0V 0V connection for serial communications This connection is common with the main electronics 0V Connector A pin 2 Pin 2 Receive RS 232 receive line RXD B D for RS 485 half duplex Pin 3 Transmit RS 232 transmit line TXD A D for RS 485 half duplex It may be necessary to use a 120 ohm termination resistor to reduce signal distortion when using RS 485 for cable run...

Page 31: ...5 m power and communications cable which is terminated at one end with a 9 pin D connector DB9 The D connector can be connected directly to a PC or to a datalogger such as the Campbell Scientific CR1000 using a suitable interconnecting cable such as the SC110 If another type of connection is required then the D connector should be removed Figure 8 2 Communications and power connections ...

Page 32: ... directly into connector B in place of the normal connector and cable One has a RS 232 or RS 485 output according to how the CS120A CS125 is configured Figure 8 4 and one has a USB output Figure 8 5 If the lid is removed take care not to overtighten the fixing screws A small gap should remain between the lid and box Figure 8 4 Configuration cable Figure 8 5 USB configuration cable NOTE ...

Page 33: ... temperatures close to 0 C are common if information on precipitation type is important It also allows RH information to be included in data messages If a CS215 is connected then the temperature used for assessment of precipitation type and included in data messages will come from the CS215 instead of the temperature sensor mounted in the cross arm The connections for the CS215 are shown below The...

Page 34: ... at power up their functions are detailed below The switches are only read during the power up sequence of the sensor This means that if the switches are pressed whilst the sensor is running nothing will happen the sensor will need to be power cycled leaving at least 10 seconds with the sensor off for any of their functions to be performed IMPORTANT CS215 WIRING COLOUR FUNCTION PIN Red 12V 1 Green...

Page 35: ...pport This change is temporary and will not be stored to flash However if the menu system is accessed and a Save and exit command is performed these new data rate settings will be committed to flash Once this switch is returned to its OFF position and the sensor is power cycled the sensor will return to its previous communications settings 2 Reserved for future use set to OFF 1 When switched to th...

Page 36: ...ited with a unique start and end character allowing easy storage into any logger see Section 15 on how to set default outputs The SYNOP Full Format message is the default message for the CS125 and the Full Format Visibility only message is the default for the CS120A STX and ETX are hexadecimal command characters Refer to Appendix B for the checksum algorithm 11 1 Visibility only messages Basic For...

Page 37: ...ITT EXT Carriage return Line feed 0x02 2 M or F 0 0 0 0 0 0 0 XXXX 0x03 0x0D 0x0A 11 2 Messages with SYNOP Present Weather Codes CS125 only SYNOP Present Weather Basic Format STX Message ID Sensor ID System status Visibility distance Visibility units SYNOP Code Checksum CCITT EXT Carriage return Line feed 0x02 3 M or F 00 99 XXXX 0x03 0x0D 0x0A SYNOP Present Weather Partial Format STX Message ID S...

Page 38: ... 0 0 0 0 0 0 00 99 XXXX 0x03 0x0D 0x0A 11 3 Messages with METAR Present Weather Codes CS125 only METAR Present Weather Basic Format STX Message ID Sensor ID System status Visibility distance Visibility units METAR Code Checksum CCITT EXT Carriage return Line feed 0x02 6 M or F XXXX 0x03 0x0D 0x0A METAR Present Weather Partial Format STX Message ID Sensor ID System status Message interval Visibilit...

Page 39: ...XXXX 0x03 0x0D 0x0A Note relative humidity is only available if a CS215 temperature and RH sensor is attached If not this field is 99 11 4 Messages with Generic SYNOP Present Weather Codes CS125 only These messages include simplified generic present weather codes such as 70 for snow which may be required for some data collection systems Generic SYNOP Present Weather Basic format STX Message ID Sen...

Page 40: ... Particle count minute Intensity mm h Generic SYNOP code SYNOP code METAR code Temperature deg C Relative humidity Checksum CCITT EXT Carriage Return Line feed 0x02 11 M or F 0 0 0 0 0 0 0 XXXX 0x03 0x0D 0x0A Message ID break down ID Definition 0 Basic format Contains only distance and system information 1 Partial format Contains user alarm outputs 2 Full format Contains all system alarms codes 3 ...

Page 41: ...down see note below ID Definition 1 One minute average 10 Ten minute average Note In accordance with WMO requirements the sensor produces visibility measurement that are either one or ten minute rolling averages that are updated at the chosen output interval or when the sensor is polled Those averages are not direct averages of MOR measurements but are averages of extinction coefficient and that a...

Page 42: ...tor DC saturation level amount of background light seen by the detector hood 0 1 0 2 0 Within limits 1 Saturated The sensor may not be able to perform visibility readings in some circumstances Possibly due to high level of reflections into the detector Hood temperature 0 3 0 1 1 2 0 Temperature is within operating conditions 1 Too low Less than 40 C 2 Too high Over 80 C 3 No sensor detected or bel...

Page 43: ...ute as defined by the WMO code table 4680 1 indicates either an error or that the sensor has been powered up less than a minute Generic SYNOP code Range Definition See Section 11 7 SYNOP weather code for the last three minutes as defined by the WMO code table 4680 simplified to give generic codes 1 indicates either an error or that the sensor has been powered up for less than one minute METAR code...

Page 44: ...riables and up to 16 additional fields Note the custom message output is only available on OS7 and above The custom message is as follows Custom format STX Message ID Unit ID System status Message interval Visibility distance Visibility units Up to 16 custom fields Checksum EOT 0x02 12 M or F X X X XXXX 0x04 There are two ways to configure the custom message The first is through the user menu syst...

Page 45: ...e This would give the following output CS125 MESSAGE SUB 4 Configure the message output format 1 Averaging duration 0 2 User alarms 0 3 System alarms 0 4 Dirty windows values 0 5 Sensor serial number 0 6 Particle count 0 7 Intensity 0 8 Accumulation 0 9 Generic SYNOP 0 10 SYNOP code 0 11 METAR code 0 12 NWS code 0 13 Temperature Degrees C 0 14 Humidity 0 15 10 minute ave vis Or type 0 to exit with...

Page 46: ...a CS125 2 This increments to 999 99 mm before resetting to zero It may be reset to zero at any time with the ACCRES command 3 Only outputs a valid value when a CS215 temperature and humidity probe is connected 12 Interface methods Device Configuration Utility Command line Menu The sensor can be set up and controlled in one of three ways The first method is by using Campbell Scientific s Device Con...

Page 47: ...he baud rate of the unit has been adjusted and then the corresponding bits per second value is entered in the port settings of the terminal emulator The sensor should now be ready to accept commands It is possible to set the sensor into the default communication state via one of the internal switches on the sensor main board See Section 9 13 Definition of the variables that can be set by the user ...

Page 48: ...value has no effect if polled mode has been selected in Measurement mode 60 12 Measurement mode 0 1 Selects polled or continuous modes In continuous mode the sensor will output a string in the format as set by Message Format at regular intervals as defined by Continuous Interval 0 Continuous mode 1 Polled mode 0 13 Message Format 0 12 Output message 0 1 and 2 Basic partial or full visibility messa...

Page 49: ...by accident 3 CS125 only 14 Command line mode The command line interface is broken down into three major commands These are GET SET and POLL The GET command is used to request all current user settable values from the sensor The SET commands sets user settable values and the POLL command is used to request the current visibility and or alarm conditions from the sensor The sensor can be configured ...

Page 50: ...ty threshold 3 Delimiting character XXXX Checksum use the valid CRC 16 checksum Delimiting character 0x03 1 ETX C 2 0x0D 1 Carriage return 0x0A Line feed 1 These values are shown in hexadecimal format not ASCII 2 As entered on a keypad 3 CS125 only 14 1 1 Example of a SET Command 14 2 The SETNC Command The format of the SETNC command is nearly exactly the same as the SET command The only functiona...

Page 51: ... 1 12 NWS code 1 11 METAR code 1 10 SYNOP code 1 9 Generic SYNOP 1 8 Accumulation 1 7 Intensity 1 6 Particle count 1 5 Sensor serial number 4 Dirty windows values 3 System alarms 2 User alarms 1 Averaging duration Delimiting character XXXX Checksum Delimiting character 0x04 Hex EOT These selections output more than one variable 1 These options will only be available if you re using a CS125 2 Only ...

Page 52: ...e a MSGSET message to set a CS125 to output temperature SYNOP code sensor serial number dirty windows values and system alarms Description of the custom message bits Bit Description 8000 Reserved 4000 Reserved 2000 Humidity 1000 Temperature Degrees C 0800 NWS code 3 0400 METAR code 0200 SYNOP code 3 0100 Generic SYNOP 3 0080 Accumulation 3 0040 Intensity 3 0020 Particle count 3 0010 Sensor serial ...

Page 53: ...e sensor To retrieve visibility data refer to the POLL command The GET command GET command transmitted data Example Description 0x02 1 STX B 2 GET GET Delimiting character 0 Address based on Sensor ID Delimiting character 0 Reserved for future use zero default Delimiting character XXXX Checksum Delimiting character 0x03 1 ETX C 2 0x0D 1 Carriage return 0x0A Line feed 1 These values are shown in he...

Page 54: ... Serial Baud Rate Sensor serial number read only Visibility Units Message interval Polling or Continuous modes Message Format RS 232 or RS 485 serial communications enabled Averaging Period Sample timing Dew heater override Hood heater override Dirty window compensation CRC 16 checking on received commands Sensor power down voltage Relative humidity threshold XXXX Checksum 0x04 1 EOT 0x0D 1 Carria...

Page 55: ... Continuous mode output interval 30 seconds Polling mode 0 continuous mode Message format 2 full message RS 232 or RS 485 serial communications 1 RS 485 Averaging period 1 minute Sample timing 1 sample per second Dew heater override 0 sensor will automatically control the dew heaters Hood heater override 0 sensor will automatically control the hood heaters Dirty window compensation 0 dirty window ...

Page 56: ...he sensor MSGGET command transmitted data Example Description 0x01 Hex SOH Delimiting character MSGGET MSG GET Delimiting character 0 Address based on Sensor ID Delimiting character 0 Payload Delimiting character XXXX Checksum Delimiting character 0x04 Hex EOT Example of the MSGGET command as sent to the sensor The message sent is The response is MSGGET 0 0 C6ED 161C 7067 ...

Page 57: ...cter XXXX Checksum 3 Delimiting character 0x03 1 ETX C 2 0x0D 1 Carriage return 0x0A Line feed 1 These values are shown in hexadecimal format not ASCII 2 As entered on a keypad 3 Not case sensitive The maximum response time to a poll command is 100 ms If the setting to check the checksum on received commands is enabled the checksum varies with the Sensor ID value The table below gives the POLL com...

Page 58: ...iting character XXXX Checksum 3 Delimiting character 0x03 1 ETX C 2 0x0D 1 Carriage return 0x0A Line feed 1 These values are shown in hexadecimal format not ASCII 2 As entered on a keypad 3 Not case sensitive Example of an ACCRES command If the setting to check the checksum on received commands is enabled the checksum varies with the Sensor ID value 15 Entering the sensor menu system The user can ...

Page 59: ...t and Save The exception to this is the calibration menu but you will be informed before any changes are made Typing 1 opens the message menu containing settings relating to the sensor s outputs Menu 1 The message output menu CS125 MESSAGE MENU 1 ID 0 S N 1006 1 Set message format FULL SYNOP 2 Toggle units METRES 3 Toggle polled or continuous mode CONTINUOUS 4 Set continuous mode message interval ...

Page 60: ...P 9 Generic Partial SYNOP 10 Generic Full SYNOP 11 Custom output 12 For example typing 2 will toggle the units through the options METRES and FEET and typing 4 will allow the message interval to be entered Option 2 allows the User Alarms to be set again by toggling through options or changing values Menu 2 The user alarm menu Menu 2 The user alarm menu Sub menu 2 Alarm two activation level Option ...

Page 61: ... containing useful information such as temperature and system alarms The parameters calibration value factory offset and calibration value factors scale are the factory calibration coefficients from the last factory calibration The parameters calibration value cal offset and calibration value cal scale are the calibration coefficients from the latest calibration NOTE CS125 CALIBRATION MENU 3 ID 0 ...

Page 62: ...arm Value Last visibility reading 3258M Overall system status 0 No faults Emitter dirty window alarm 0 0 Emitter internal temperature 0 38 4 Detector dirty window alarm 0 0 Detector internal temperature 0 31 0 Detector DC light saturation 0 Hood heater temperature 0 25 6 CS125 Calibrator Serial No 1000 CS125 Calibrator Exco 30 5 Calibration value factory offset 0 026 Calibration value factory scal...

Page 63: ...up battery The RH threshold for a CS125 can also be set from this menu This applies if a CS215 sensor is attached and defines the level of RH below which obscuration is deemed to be dry that is haze SYNOP 04 or 05 METAR HZ rather than wet mist SYNOP 10 METAR BR or fog SYNOP 30 etc METAR FG NOTE CS125 COMMUNICATIONS MENU 5 ID 0 S N 1009 1 Set sensor ID 2 Set RS 232 RS 485 baud rate 38400 3 Toggle R...

Page 64: ...o temporarily set the sensor to RS 232 mode 38400 bps If the sensor is already set in RS 232 mode it should not be necessary to change any internal switches See Section 10 for more information on the sensor internal switches The test should ideally be performed in the following conditions Ambient temperature should be between 0ºC and 50ºC The local visibility should be approximately 10 000 metres ...

Page 65: ...ore information A simple visual check may be enough to confirm the lenses are clean Once you have started the tests you will be asked for the sensor calibrator serial number and extinction coefficient with a confirmation at each step giving you the chance to correct typing mistakes When asked for confirmation you do not need to press return after you type y NOTE NOTE Starting calibration Input the...

Page 66: ...into each hood If either of the bungs are damaged or appear to have any gaps around the edge please contact Campbell Scientific This part of the test will take approximately two minutes Every ten seconds a dot should appear indicating that the test is progressing as normal Remove the bungs once the sensor instructs you to Place the sensor calibrator into the volume by fastening it to the central m...

Page 67: ...etting can be viewed from menu item 4 from the main menu once the test is completed 16 2 Dirty window zero calibration Option 3 in the calibration menu allows the user to reset the zero contamination level for dirty windows detection option 4 allows a return to the factory value if something goes wrong with the calibration process This should be carried out every two years to check for any slight ...

Page 68: ...y key to exit Not return Press any key and the dirty window zero offset calibration is complete 16 3 Internal temperature check CS125 only The CS125 has an internal temperature sensor in one of the cross arms This is used as part of the present weather identification if a CS215 temperature and RH sensor is not connected This does not need recalibration but can be checked if a suitable nearby refer...

Page 69: ...ange requires RS 232 communication If a sesor is set to communicate by RS 485 it can be temporarily set to RS 232 with switch 3 see Section 10 Figure 17 1 Sensor DevConfig download instructions Figure 17 2 Sensor DevConfig screen when OS update is complete NOTE ...

Page 70: ...t prone to contaminants and monthly intervals for those prone to contamination roadside or airport use In some cases more frequent cleaning may be required where there are high levels of contaminants and high dependency on the instrument output If the lenses require cleaning it is very important that only a proper lens cloth or lens tissue be used The use of inappropriate materials to clean the le...

Page 71: ...cur if any other type of heating unit or appliance is used 2 When placed in a forced air circulating air or convection oven allow a minimum of 4 to 5 cm of air space between the top of the bags and the next metal tray above the bags If placed in a radiating exposed infrared element type oven shield the bags from direct exposure to the heating element giving the closest bags a minimum of 40 cm clea...

Page 72: ... prevents moisture from coming into contact with the regenerated desiccant Some care should be taken when re activating desiccant bags If heated in an oven which is too hot the bags may burst If in any doubt we recommend purchasing new desiccant packs instead of oven drying Failure to use or exchange the desiccant may lead to condensation inside the enclosure Not only will this lead to corrupted d...

Page 73: ...A 1 Appendix A CS120A CS125 block diagram ...

Page 74: ...CS120A and CS125 Visibility and Present Weather Sensors A 2 ...

Page 75: ...sum seeded with 0x0000 XModem style using a fast non table based algorithm Pass in the data to convert into a CRC 16 in the form of a NULL terminated character array a string Returns the CRC 16 in the form of an unsigned 16 bit integer value Note This algorithm has only been tested on a native 16 bit processor with a hardware barrel shifter All integers are 16 bits long unsigned int CRC 16_CCITT c...

Page 76: ...CS120A and CS125 Visibility and Present Weather Sensors B 2 ...

Page 77: ...dest 11 Emitter_lens_dirty 0 3 Emitter Lens Dirty Alias SerialIndest 12 Emitter_temp_error 0 3 Emitter Temperature Alias SerialIndest 13 Detector_lens_dirty 0 3 Detector Lens Dirty Alias SerialIndest 14 Detector_temp_error 0 3 Detector Temperature Alias SerialIndest 15 Detector_saturated 0 1 Detector DC Saturation Level Alias SerialIndest 16 Hood_temp_error 0 3 Hood Temperature Alias SerialIndest ...

Page 78: ... received checksum is valid Calculate the expected checksum lngCRCCalc CheckSum InString 1 NBytesReturned 5 Extract the checksum from the message convert it for comparison lngCRCMsg HexToDec checksumrx ChecksumOK lngCRCMsg lngCRCCalc In critical applications the visibility can be set to NaN if the system status is degraded or a critical error flag is set If ChecksumOK Then Visibility Visibilitystr...

Page 79: ... Lens Dirty Alias SerialIndest 14 Detector_temp_error 0 3 Detector Temperature Alias SerialIndest 15 Detector_saturated 0 1 Detector DC Saturation Level Alias SerialIndest 16 Hood_temp_error 0 3 Hood Temperature Alias SerialIndest 17 External_temp_error 0 3 External Temperature Alias SerialIndest 18 Signature_error 0 1 Signature Error Alias SerialIndest 19 Flash_read_error 0 1 Flash Read Error Ali...

Page 80: ... InString h02 0 h03 NBytesReturned 01 Check that a message has been recieved first If NBytesReturned 0 Then SplitStr SerialIndest InString 27 5 Check the received checksum is valid Calculate the expected checksum lngCRCCalc CheckSum InString 1 NBytesReturned 5 Extract the checksum from the message convert it for comparison lngCRCMsg HexToDec checksumrx ChecksumOK lngCRCMsg lngCRCCalc In critical a...

Page 81: ...lows 1 Sensor ID 2 User Alarm 1 Set 3 User Alarm 1 Active 4 User Alarm 1 Distance 5 User Alarm 2 6 User Alarm 2 Active 7 User Alarm 2 Distance 8 Serial BaudRate 9 Serial number Read only so not used 10 Visibility Units 11 Continuous mode output interval 12 Polling Or Continuous modes 13 Message Format Basic Partial Full 14 RS232 or RS485 serial communications enabled 15 Averaging Period 16 Sample ...

Page 82: ...alarm 2 trigger distance to 15000 CS125CArray 8 2 Set serial baud rate to 38400bps CS125CArray 9 0 Read only so dummy value added here but not needed CS125CArray 10 M Set unit type to metres use upper case CS125CArray 11 60 Set output period to 60 seconds CS125CArray 12 1 Polling mode CS125CArray 13 2 Set FULL output message format CS125CArray 14 0 Set RS232 serial mode CS125CArray 15 1 Set averag...

Page 83: ...ter Dim TempString As String 100 Alias TRHData 1 AirTC Alias TRHData 2 RH This function creates a SETNC command string for the CS125 visibility sensor Including all delimiting characters and checksums then returns the string in CS125CommandString Array variable order is as follows 1 Sensor ID 2 User Alarm 1 Set 3 User Alarm 1 Active 4 User Alarm 1 Distance 5 User Alarm 2 6 User Alarm 2 Active 7 Us...

Page 84: ...ry but is done as a fail safe in case the GET command does not return data CS125CArray 1 0 Set ID to 0 CS125CArray 2 0 Disable alarm 1 CS125CArray 3 1 Set alarm 1 to if greater than CS125CArray 4 10000 Set alarm 1 trigger distance to 10000 CS125CArray 5 0 Disable alarm 2 CS125CArray 6 0 Set alarm 2 to if less than CS125CArray 7 10000 Set alarm 2 trigger distance to 10000 CS125CArray 8 0 Set serial...

Page 85: ...InStringGET 1 Then Check data was returned SplitStr CS125CArray 1 InStringGET 21 5 Strip the settings from the returned data string CS125CArray 1 Right CS125CArray 1 1 Trim the SOT from the first data point EndIf Enable Dew Heaters if AirTC DewPoint If AirTC TempDewPoint AND StatusDewHeater False Then CS125CArray 17 0 SerialFlush Com1 TempString CS125_SETNCCommand SerialOut Com1 TempString 0 100 D...

Page 86: ...s String 40 Outgoing string Dim CheckVal As Long Checksum value Public InString As String 200 Incomming string Dim TempString As String 16 Main Program BeginProg SerialOpen Com1 38400 3 0 10000 open port to the visibility sensor Send a request for information once every 10 seconds Scan 10 Sec 0 0 Create the basic GET string for the CS125 TempString GET 0 0 CheckVal CheckSum TempString 1 0 Use the ...

Page 87: ... the values going out to the CS125 Output the dirty window values the sensor serial number SYNOP codes and the outside temperature Bit Description Value Nibble value 16 Reserved 15 Reserved 14 Humidity 0 0x1 13 Temperature Degrees C 1 12 NWS code 3 0 0x2 11 METAR code 0 10 SYNOP code 3 1 9 Generic SYNOP 3 0 8 Accumulation 3 0 0x1 7 Intensity 3 0 6 Particle count 3 0 5 Sensor serial number 1 4 Dirt...

Page 88: ...d CS125 Visibility and Present Weather Sensors C 12 SerialIn MSG_Response Com1 100 0 1000 Grab returned data from the sensor Returned data is identical to the data a MSGGET command would return NextScan EndProg ...

Page 89: ... 9 0 587C Public CS120CommandString As String 40 CheckValCCITT Public MSG_Response As String 100 Public TempString As String Main Program BeginProg open port to the visibility sensor SerialOpen Com1 38400 3 0 10000 Scan 10 Sec 0 0 Create the main part of the message TempString MSGGET 0 0 Add the checksum and command characters CheckValCCITT CheckSum TempString 1 0 CS120CommandString CHR 2 TempStri...

Page 90: ......

Page 91: ...me 35 PRECIPITATION 40 Precipitation slight or moderate 41 Precipitation heavy 42 Solid precipitation slight or moderate 45 Freezing precipitation slight or moderate 47 Freezing precipitation heavy 48 DRIZZLE 50 Drizzle not freezing slight 51 Drizzle not freezing moderate 52 Drizzle not freezing heavy 53 Drizzle freezing slight 54 Drizzle freezing moderate 55 Drizzle freezing heavy 56 Drizzle and ...

Page 92: ...an be output by the sensor UP Unidentified precipitation HZ Haze BR Mist FG Fog DZ Drizzle RA Rain SG Snow grains SN Snow PL Ice pellets Notes HZ will only be reported if a CS215 is connected to allow relative humidity information to be available FZ freezing may be added as a descriptor in front of BR FG DZ and RZ Intensity qualifiers for light for heavy may be added in front of DZ RA SN and PL Co...

Page 93: ...Appendix D Present Weather Codes D 3 ...

Page 94: ...NW Edmonton Alberta T5L 4X4 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc info campbellsci cc Campbell Scientific Ltd CSL 80 Hathern Road Shepshed Loughborough LE12 9GX UNITED KINGDOM www campbellsci co uk sales campbellsci co uk Campbell Scientific Ltd Franc...

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