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Sentry™ Visibility Sensor User's Guide

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1. e 1 Figure 5 4 2 1 Signal Processor Diagnostic Test Points Table 5 4 2 1 2 2 Tolerance TP 1 12 0 0 5 VDC TP3 12 0 0 5 VDC TP4 5 0 0 25 VDC OFF normal ON incomplete current loop TP6 5 Vp p 2600 200 Hz 48 May 2007 Sentry Visibility Sensor User s Guide AC Versions If TP1 or are out of tolerance measure the voltages from the main Power Supply as shown in Figure 5 4 2 2 and the Table 5 4 2 2 below Use the power supply terminal marked Com as the ground reference Table 5 4 2 2 Name Wire Color Tolerance 2 Red 15 0 0 5 VDC COM Black 15 VDC Return White 15 0 0 5 VDC 447 4 5 Green 5 0 0 25 VDC Load Resistors Ni Power Cable to 1 of Signal Processor PCB AC Power Indicator 4 Figure 5 4 2 2 AC Power Supply Test Points 1 If the AC Power Supply voltages are within tolerance but the Signal Processor voltages are out of tolerance replace the sensor per the general installation instructions in Section 2 2 If the AC Power Supply voltages are out of tolerance replace the AC Power Supply per the remove amp replace instructions in Section 5 4 4 DC Versions If TP1 TP3 or 4 are out of tolerance measure the voltages from the DC Power S
2. sosuag 31119151 uos 95 pnis amp insopxr3 0 punog uue3 panys 9E 0L NE Cy yn y DO PN 9 01 10 890006 5 20006 N d 82d XL L000 82d XH pooH pooH 8 0100t w02 s10suesu ajouiue p ojul 0102 18 017 9658 501 eiqunjo2 wingeelg 80L ou 5 Loug 8 wu JV eur ov JennaN Ov puna 0 0 2 001 10 LC00 Nid 5 OV 31naow 39uns 8 secs 9 DYA 78 rs 3191 9NIHIM DV LL 20006 Nid 82d XL 0006 Nid 82d XH Figure A 3 Sentry Schematic Optional Hood Heaters May 2007 59 P N 80002 Sentry Visibility Sensor User s Guide Wittich amp Visser bv Phone 31 70 3070706 P O Box 1111 Fax 31 70 3070938 2280 CC Rijswijk info wittich nl The Netherlands
3. Visibility Sensor User s Guide Model SVS1 Analog Output Version May 2007 Wittich amp Visser bv P O Box 1111 Phone 31 70 3070706 2280 CC Fax 31 70 3070938 The Netherlands info wittich nl Revision History Rev Date Description of Changes 11 30 02 New Release 2 5 03 Change low range to 30 meters change Fig 4 0 1 amp 4 1 2 for new ND filter Update for new DC Power Supply change Fig 2 4 2 1 amp 5 4 2 3 Minor change to Output Option PCB Add calibration section for 4 20 ma 4 15 03 Minor corrections to DC Power Supply amp Output Option images Removed reference to RS 232 output added CE Mark hood heater schematic altered Fig 4 1 1 to add new Signal Proc PCB layout 9 12 03 Add 3 V full scale option for Davis Vantage Pro interface 2 5 04 Minor corrections 3 22 04 Add 1 pipe mount option 9 20 04 Change data processing algorithm example in Section 3 1 amp 3 2 Change description about yellow LED for 4 20 ma operation in Section 3 2 Add note about output voltage saturation to Section 3 1 8 18 05 Add P N30005 3 Relay Output option May 2007 Changed P N s 4 20 ma wiring options 3 15 03 8 5 03 4 18 05 This equipment is in compliance with the essential requirements and other provisions of Low Voltage Directives 73 23 EEC and 89 336 EEC as amended by Directive 93 68 EEC WEEE and RoHS Statement Envirotech Sensors is pursuing compliance with human safety and environmental pro
4. 0000 47 54 EE ERE 48 5 4 1 Tilia Loo 48 54 27 eem p 48 5 4 3 Troubleshooting Scenarios oie t e eat e t ede aeo a e eed d 51 5 4 4 Remove amp Replace 1 11 52 5 5 Field Replaceable Units ERU as cr E E EE ERE RR ERE ERN 54 5 6 Training s 54 ANa 6121 01 Ss ip LII IET 55 P N 80002 iii May 2007 List of Figures Figure 1 1 1 Forward Scatter 2 Fig re 1221512 Sensor 4 Figure 1 3 1 Sentry Major Components 9 Figure 1 3 2 Main Enclosure Components AC Power Version 11 Figure 1 3 3 Main Enclosure Components DC Power Version 13 Figure 1 4 1 Sentry Signal Flow Diagram eeeeeeeeeeeeeeeee nenne enne nene n nnnm nnnm nuin nns nnn annt nnmnnn 14 Figure 2 1 1 1 Sensor Orientation xo Ceu aos e REP NACER Ace 15 Figure 2 1 1 2 Typical Roadside Installation nnne nnn 16 Figure 2 1 1 3 Typical Tunnel 16
5. 5 COMMON DC DC Converter Module 15V a iP4 ae EnviroTech Sensors Inc ASSY 30068 9 0 n 10 36 VDC r Remote ON OFF 0 Figure 2 4 2 1 User DC Power Wiring P N 80002 27 May 2007 Sentry Visibility Sensor User s Guide 2 4 3 Earth Grounding Connections Earth grounding is required to insure that the surge protection devices in the sensor work properly In addition it also provides a safety ground that may be required by local electrical codes 14 20 threaded stud is provided on the bottom of the Sentry Main Electronics Enclosure for this purpose Refer to Figure 2 4 3 1 for an illustration of proper grounding 1 Drive an 8 10 foot long copper clad ground rod into the earth adjacent to the sensor support structure 2 Connect a customer supplied large gauge copper wire 4 AWG 21 mm typical from the 4 20 ground stud on the bottom of the Sentry M enclosure to the ground rod using the shortest length of wire Do not over tighten the 14 20 nut Ground Rod Figure 2 4 3 1 Earth Grounding P N 80002 28 May 2007 Sentry Visibility Sensor User s Guide 3 0 Data Interpretation and Operation Interpretation of the data depends on which visibility range and output option was ordered with your sensor Read the product label on the outside of the Main Electronics Enclosure door and compare the part number as fol
6. nennen nnne nnne nnne nnne nnne nnne nannten 42 Figure 4 1 3 Installing the Scatter 42 Figure 5 4 1 1 LED 18 2 eer Deca ee cua ceu iiec ei iet rea eie 48 Figure 5 4 2 1 Signal Processor Diagnostic Test Points cessent 48 Figure 5 4 2 2 AC Power Supply Test Points 49 Figure 5 4 2 3 DC Power Supply Test Points 50 Figure 5 4 4 1 Surge Module nennen nennen ennt nnnm annnm annt nnn snnt 52 Figure A 1 Sentry Schematic AC 1 nnnm annt 56 Figure A 2 Sentry Schematic DC 58 Figure A 3 Sentry Schematic Optional Hood Heaters esee eene 59 Notes Cautions Warnings This User s Guide clearly identifies notes cautions and warnings EnviroTech Sensors recommends that the user read the complete User s Guide before proceeding with the sensor installation and maintenance Areas in the User s Guide that involve potential contact w
7. In 19 2 3 1 Analog Voltage Output 19 2 3 2 4 20 ma Current Loop Output 22 4 21 2 39 8 3 Output Connection for P N 30005 xxx 23 2 4 Electrical Power Installation oe 25 2 4 1 Power ht qute 25 2 4 Power Connections 26 24 3 Earth Grounding cna y tun 28 3 0 Data Interpretation and Operation 29 3 1 Analog Voltage 29 3 2 4 20 ma Current Loop Output Optional 34 3 3 P N 30005 3 Relay Output Optional mte eine eau chen ter con oe 38 APO Calibration ML NU 40 4 1 Procedure for Calibrating the Analog Voltage Output Sentry Sensor 41 4 2 Procedure for Calibrating the Sentry with 4 20 ma Current Output 44 5 05 EET EM TEM 46 5 1 EnviroTech Sensor Inc Product 46 5 2 Correcting Defects Under the 46 5 3 Preventative
8. Fo le EMT cis RT T C6 E o UB D C25 J4 H o pD o 0 OQ 6 0 1 R23 I He 9 4 E D4 a 1 Hf ENVIRQTECH SENSORS INC assy 30007 S N D VDC Out VDC Return Figure 2 3 1 1 Analog Output Voltage Connections P N 80002 20 May 2007 Sentry Visibility Sensor User s Guide 2 3 2 4 20 ma Current Loop Output Connection The Sentry 4 20 ma output options are part of the Signal Processor PCB in the Main Electronics Enclosure The PCB is factory configured for either single ended A or isolated B 4 20 ma depending on the option ordered User connections are made to TB1 of the Signal Processor PCB 1 2 Loosen the cord grip on the lower left bottom of the Main Electronics Enclosure Feed a twisted shielded pair cable into the enclosure through the cord grip 22 AWG 0 326 mm or larger wire is recommended The cable run may be as long as necessary provided the total resistance of the entire loop including outgoing wire customer data acquisition system resistance and return wire is 500 ohms Strip 6 mm 1 4 of insulation from each of the two conductors and connect them to TB1 using the information in Table 2 3 2 1 and Figure 2 3 2 1 Table 2 3 2 1 TB1 Terminal Function 3 4 ma Out 4 ma Return Tighten the cord grip to secure the signal cable Connect the other end of the cable to the us
9. 048 0 300 10 0000 10000 6 214 32810 0 0250 4 040 0 250 12 0000 12000 7 457 39372 0 0200 4 032 0 200 15 0000 15000 9 321 49215 0 0187 4 030 0 187 16 0858 16086 9996 52777 P N 80002 36 May 2007 Sentry Visibility Sensor User s Guide Table 3 2 4 SENTRY VISIBILITY SENSOR OUTPUT Optional 10m 10 Km Visibility Range Sentry Sentry EXCO MOR MOR MOR MOR Voltage Current ma 1 ft 10 0000 20 000 300 000 0 010 10 0 006 33 9 0000 18 400 270 000 0 011 11 0 007 36 8 0000 16 800 240 000 0 013 13 0 008 41 7 0000 15 200 210 000 0 014 14 0 009 47 6 0000 13 600 180 000 0 017 17 0 010 55 5 0000 12 000 150 000 0 020 20 0 012 66 4 0000 10 400 120 000 0 025 25 0 016 82 3 0000 8 800 90 000 0 033 33 0 021 109 2 0000 7 200 60 000 0 050 50 0 031 164 1 2500 6 000 37 500 0 080 80 0 050 262 0 7500 5 200 22 500 0 133 133 0 083 437 0 5000 4 800 15 000 0 200 200 0 124 656 0 2500 4 400 7 500 0 400 400 0 249 1312 0 1000 4 160 3 000 1 000 1000 0 621 3281 0 0500 4 080 1 500 2 000 2000 1 243 6562 0 0450 4 072 1 350 2 222 2222 1 381 7291 0 0400 4 064 1 200 2 500 2500 1 554 8202 0 0350 4 056 1 050 2 857 2857 1 775 9374 0 0300 4 048 0 900 3 333 3333 2 071 10937 0 0250 4 040 0 750 4 000 4000 2 486 13124 0 0200 4 032 0 600 5 000 5000 3 107 16405 0 0150 4 024 0 450 6 667 6667 4 143 21873 0 0125 4 020 0 375 8 000 8000
10. 4 971 26248 0 0100 4 016 0 300 10 000 10000 6 214 32810 80002 37 May 2007 Sentry Visibility Sensor User s Guide 3 3 P N 30005 3 Relay Output Optional Control Relay 1 The customer must set the threshold of the control relay 1 If both control relays were ordered set Control Relay 1 to the higher of the 2 control relay thresholds i e 3000 m Figure 3 3 1 and the procedure steps below provide the details of setting up the control relay threshold 1 Select the visibility at which the control relay should activate Use the formulas in Section 3 1 and Table 3 1 1 for a 0 10 VDC output sensor to determine an equivalent sensor output voltage For example the equivalent sensor voltage for a threshold of 3 kilometers is calculated as follows Sensor VDC 0 300 3 km 0 100 VDC 30m 16 km standard visibility range Sensor VDC 0 100 3 km 0 033 VDC 10m 10 km optional visibility range 2 3 4 Totest the relay connect an ohmmeter to across the CCOM1 and terminals of Connect a digital voltmeter to TP2 and TP8 Adjust R13 to set the threshold voltage to the voltage obtained above TB1 Wave your hand in the Sentry sample volume to increase the sensor output and observe that the ohmmeter switches from open to short Control 2 Threshold Control 1 Threshold P N 80002 ENWR TECH SENSORS INC R2 assy MEO05 e a DVM
11. 5000 1500 0 932 4921 0 0500 0 500 6 0000 6000 3 728 19685 1 000 3 0000 3000 1 864 9842 0 0400 0 400 7 5000 7500 4 661 24606 0 800 3 7500 3750 2 330 12303 0 0300 0 300 10 0000 10000 6 214 32808 0 600 5 0000 5000 3 107 16404 0 0250 0 250 12 0000 12000 7 457 39370 0 500 6 0000 6000 3 728 19685 0 0200 0 200 15 0000 15000 9 321 49212 0 400 7 5000 7500 4 661 24606 0 0186 0 186 16 1031 16103 10 006 52831 0 373 8 0515 8052 5 003 26415 0 0150 0 300 10 0000 10000 6 214 32808 0 0125 0 250 12 0000 12000 7 457 39370 0 00932 0 186 16 0944 16094 10 001 52803 P N 80002 32 May 2007 Sentry Visibility Sensor User s Guide Table 3 1 4 SENTRY VISIBILITY SENSOR OUTPUT CURVE Optional 10m 10 Km Visibility Range 10 VDC Full Scale Output 5 VDC Full scale Output Sentry EXCO MOR MOR MOR MOR EXCO MOR MOR MOR MOR Voltage 1 ft 1 ft 10 0000 300 000 0 0100 10 0 006 33 9 0000 270 000 0 0111 11 0 007 36 8 0000 240 000 0 0125 13 0 008 41 7 0000 210 000 0 0143 14 0 009 47 6 0000 180 000 0 0167 17 0 010 55 5 0000 150 000 0 0200 20 0 012 66 300 000 0 0100 10 0 006 33 4 0000 120 000 0 02
12. Archive averaged data once per minute Table 3 2 3 below shows the relationship between sensor output current extinction coefficient EXCO and equivalent MOR visibility in kilometers meters and statute miles and feet for both the standard 30m 16 km visibility range and 0 10 VDC and 0 5 VDC voltage outputs Table 3 2 4 repeats this information for the optional 10m 10 km visibility range P N 80002 35 May 2007 Sentry Visibility Sensor User s Guide Table 3 2 3 SENTRY VISIBILITY SENSOR OUTPUT Standard 30 16 Km Visibility Range Sentry 2 MOR MOR MOR Voltage Brent km 1 km m m MOR it ma 10 0000 20 000 100 000 0 0300 30 0 019 98 9 0000 18 400 90 000 0 0333 33 0 021 109 8 0000 16 800 80 000 0 0875 38 0 023 123 7 0000 15 200 70 000 0 0429 43 0 027 141 6 0000 13 600 60 000 0 0500 50 0 031 164 5 0000 12 000 50 000 0 0600 60 0 037 197 4 0000 10 400 40 000 0 0750 75 0 047 246 3 0000 8 800 30 000 01000 100 0 062 328 2 0000 7 200 20 000 01500 150 0 093 492 1 0000 5 600 10 000 0 3000 300 0 186 984 0 7500 5 200 7 500 0 4000 400 0249 1312 0 5000 4 800 5 000 0 6000 600 0373 1969 0 2500 4 400 2 500 12000 1200 0 746 3937 0 1000 4 160 1 000 3 0000 3000 1 864 9843 0 0500 4 080 0 500 6 0000 6000 3728 19686 0 0400 4 064 0 400 7 5000 7500 4 661 24607 0 0300 4
13. Warranty Contact EnviroTech Sensors to discuss the reason for returning a product and to obtain the return material authorization RMA number Items to be returned to EnviroTech Sensors for any reason must be accompanied by a return material authorization number Mark the outside of all shipping cartons and correspondence with the RMA number Buyer shall return the product to EnviroTech Sensors prepaid transportation Upon receipt EnviroTech Sensors will evaluate the product to determine the cause of the reported problem and the applicability of the warranty Products deemed to be covered by the warranty will be repaired by EnviroTech Sensors at no charge to the Buyer and returned to the Buyer prepaid surface transportation EnviroTech Sensors will prepare an estimate for products not under warranty and submit the quotation to the Buyer for approval Contact EnviroTech Sensors or visit http www envirotechsensors com for information on the return of waste electrical parts per WEEE The Waste Electronic and Electrical Equipment Directive directive 2002 96 EC NOTE EnviroTech Sensors Inc can provide field service of its products including installation maintenance and repair Contact us for field service rates and information on annual service plans P N 80002 46 May 2007 Sentry Visibility Sensor User s Guide 5 3 Preventative Maintenance Regular field maintenance is recommended to keep the Sentry is good working or
14. When selecting which side of the tower to use make certain that the sensor sample volume is 1 5m a 3 4 ft gt U Bolts 2 PLCS 1 inch Sch facing away from the tower and not over dore the boom arm while still aligning the receiver optics facing in a northerly L 3 Leg Rohn direction or parallel with the roadway Type Tower Figure 2 1 2 2 Site Preparation Tower Boom Arm Earth Grounding The Sentry must be grounded to an approved earth terminal for electrical safety and for the built in lightning protection circuitry to work properly This wiring is in addition to the ground wire that is part of the power wiring A typical ground rod is shown at right Additional information on earth grounding is found in Section 2 3 3 P N 80002 17 May 2007 Sentry Visibility Sensor User s Guide e Power The Sentry requires a source of single phase power unless the 12 VDC option was ordered at 1 A current Consideration should be made to add power and signal junction boxes near the sensor during the construction phase Additional information on AC wiring is found in Section 2 3 1 e Signal Wiring The rule of thumb is that the shorter the signal wire the better EnviroTech Sensors recommends that signal wires be 15 m 50 ft and 22 AWG 0 326 mm or larger wire gauge Exceptions to this rule are made for the optional 4 20 ma current loop output option and the control
15. closed NC contacts and are rated at 100 VDC 0 25A Many combinations of the 274 character group are possible but some are mutually exclusive For instance a character group of CDE indicates that the sensor is supplied with control relay 1 diagnostic relay and control relay 2 Contact EnviroTech Sensors if you have a question P N 80002 5 May 2007 Sentry Visibility Sensor User s Guide 1 2 1 3 Hood Heater Options The 3 option character describes the hood heater options as described in Table 1 2 1 4 1 Table 1 2 1 4 1 When the 3 2 character is Then REESE Los EA No external hood blank heaters installed Silicone resistance heaters are installed under each black metal hood that covers the front of the transmitter and receiver heads to prevent blowing snow from clogging the sensor s optical path Thermostatically controlled to automatically turn on at 3 C and off at 8 C With AC powered sensors each hood heater consumes 25 W of power from a 24 VAC transformer in the Sentry Electronics Enclosure With 12 VDC powered sensors each hood heater consumes 6 W of power from the 12 VDC input power Heaters are included 1 2 1 4 Mounting Flange Options The 4 option character describes the flange mounting options as described in Table 1 2 1 5 1 Table 1 2 1 5 1 When tne 2 Description character is Then This is the standard Sentry mounting flange best
16. coefficient P N 80002 1 May 2007 Sentry Visibility Sensor User s Guide Most users will use only the Koschmieder s V 3 6 formula The aviation community typically uses a photometer to measure the day night condition and applies both formulas depending on the ambient background light Fortunately sensors have been developed that can reliability measure visibility They employ one of two methods to measure atmospheric visibility either transmissivity or scattering Sensors that measure the transmissivity of the atmosphere transmissometers are research tools that are often used as standards against which other sensors are compared They are not practical for most automated systems due to their high cost to purchase install and maintain 1 14 How the Sentry Works The Sentry uses the principle of forward scattering as shown in Figure 1 1 1 The optical System is designed such that the infrared light projected from the transmitter TX intersects the field of view of the receiver RX with a forward angle of 427 The area of intersection is known as the sample volume The 42 forward angle ensures performance over a wide range of particle sizes in the sample volume including smoke dust haze fog rain and snow When the air is clear very little light is scattered since there are few particles in the sample volume resulting in a small signal received by the sensor As the number of particles in the sample volume increases the am
17. of TB1 on the DC power PCB the DC DC converter is put into the sleep mode until the ground is released This may be controlled by a standard TTL line or I O port Additional information is contained in Section 2 4 2 Signal Processor PCB P N 30007 This PCB provides signal and DC power distribution to all sensor components The received signal from the RX PCB is demodulated using the synchronization pulses from the TX PCB After demodulation the signal is filtered through a low pass filter amplified and scaled to the appropriate level The output voltage passes through EMI filtering and surge protection before being made available to the user as an analog voltage The Signal processor also contains test points and an array of LEDs D1 that indicate sensor status In normal operation 3 of the LEDs are on continuously one is off or on based on connection of the optional 4 20 ma current loop and one LED is blinking approximately once every 2 seconds Additional information on the diagnostics and test points is contained in Section 5 Maintenance The analog output voltage or 4 20 ma output current is EMI filtered surge protected and available for user connections via an onboard terminal strip TB1 3 Relay Output Option PCB P N 30005 This PCB plugs into the circuit card guides provided on the Signal Processor PCB and provides up to 3 relay outputs that may be ordered with the sensor The PCB receives power and signals f
18. power supply and test point checks described above have been completed Case 1 Visibility too high sensor analog output too low for long periods when it is obvious that the ambient visibility is low i e foggy Check for lens blockage due to snow or wet blowing leaves clear as needed Check for lens heater operation by feeling the lens with your finger The lens should be warmer than the TX RX head area around the heated lens replace sensor if lens heater not operational or condensation continues to be a problem Check for physical damage to the sensor heads or cross arm Misalignment of these parts will result in TX and RX beams not intersecting correctly replace sensor Observe that the TX LED is operating by looking at the the beam under the hood through the optics This test is best performed in low light It should glow red in color Problem could be internal to the sensor replace sensor per the general installation instructions in Section 2 Case 2 Visibility too low sensor analog output too high for long periods when it is obvious that ambient visibility is high i e clear Check for spider webs or insect nests under the hoods or anywhere within the sensor sample volume clean as needed Check for other sources of interference that would cause light scattering such as physical damage to hoods or other parts of the head remove interference or replace sensor as needed Problem could be internal to
19. relay option where the cable may be much longer 2 2 Mechanical Installation Once the site preparation is complete physically installing the Sentry is simple Follow these steps to complete the mechanical installation as shown in Figure 2 2 1 When unpacking the sensor carefully remove the packing material and lift the sensor out of the shipping carton If the sensor must be laid down lay it flat with the front door of the Main Electronics Enclosure down to avoid any damage to the sensor heads or hoods Equipmen 91 1 or 1 12 Sensor Mounting 3 8 16 Hex Head Flange Bolts 2 PLCS User Supplied Mounting Pole 1 Remove the sensor from the shipping carton and inspect for obvious damage 2 Lift the sensor over the mounting pole and carefully lower it to engage the flange 3 Rotate the sensor per the instructions in Section 2 1 1 above 4 Tighten the two 2 3 8 16 hex head bolts in the flange to secure the sensor to the pole 5 Go to Section 2 3 to connect the signal wiring P N 80002 18 May 2007 Sentry Visibility Sensor User s Guide 2 3 Signal Wiring The signal wiring depends on the output option that was supplied with the sensor Read the serial number label on the outside of the Main Electronics Enclosure door and compare the part number in Table 2 3 1 as follows Table 2 3 1 If your P N is Then your output is See section SVS1 x 1 0 10 VDC analog 2 3 1 SVS1 x 2 0 5 VDC analog 2 3 1 SVS1 x A 4
20. the AC Power Supply and Surge Protection Module are ON 12 VDC 3 Observe LED array on the Signal Processor PCB It should be illuminated as shown in Figure 5 4 1 1 The ALM LED is only used with 12 VDC the 4 20 ma option If correctly wired the ALM LED should be OFF 5 42 Test Points Equipment required e 3 1 2 Digit Digital Volt Meter e Oscilloscope 1 Measure the power supply voltages at TP1 TP3 amp TP4 of the Signal Processor PCB as indicated in Figure 5 4 2 1 and verify that they are within tolerance as listed in Table 5 4 2 1 Use TP2 as the ground reference 2 If LED 5 is not blinking 30 times per minute 1 2 Hz measure the SYNC pulse at TP6 using oscilloscope If the SYNC is of tolerance replace the sensor per the general installation instructions in Section 2 k LED Status 1 ON 2 ON 3 ON 4 OFF 5 BLINKING P N 80002 Indication 12 VDC 12 VDC 5 VDC 4 20 ma SYNC D1 Figure 5 4 1 1 LED Display 12 VDC 12 VDC Diagnostic SV 12V 45V ALM SYNC o o o 5 VDC 1 COM
21. the sensor replace sensor per the general installation instructions in Section 2 P N 80002 51 May 2007 Sentry Visibility Sensor User s Guide 5 4 4 Remove amp Replace Instructions Only certain parts of the Sentry may be replaced in the field The TX and RX Heads are not field repairable and should not be opened The Signal Processor PCB in the Main Electronics Enclosure is not field replaceable Contact EnviroTech Sensors if you have a question about what is repairable or replaceable in the field Instructions to remove and replace Sentry s components are listed below Remember that the Sentry contains hazardous mains voltages and should only be serviced by authorized personnel who have fully read and understand this User s Guide Equipment required Flat blade screwdrivers 2 Phillips screwdriver rrr mn voltage 3 8 nut driver Adjustable wrench personnel may service ihis equipment Needle nosed pliers Wire cutters Surge Protection Module Turn AC or DC power OFF before proceeding with the removal and replacement instructions provided in this Section Removal Using a small flat blade screwdriver loosen the 3 AC input wires on the left side of the module Loosen the 3 AC output wires from the right side of the module Loosen the hold down screw on the lower DIN rail clamp and lift the clamp off the rail to free the module Slide the module down and off the rail Replacement Place the n
22. 0 0000 10000 6 214 32808 P N 80002 33 May 2007 Sentry Visibility Sensor User s Guide 3 2 4 20 ma Current Loop Output Optional The operation of the Sentry is the same for both the single ended 4 20 ma Sensor P N SVS1 x A and the isolated 4 20 ma Sensor P N SVS1 B options The sensor current output ma must be converted to extinction coefficient o or visibility MOR in the appropriate units of measure Most users should convert directly from current to visibility using one of the formulas in Table 3 2 1 Table 3 2 1 30m 16 km Range 10m 10 km Range Viel OS 4 20 ma Output 4 20 ma Output of Measure Kilometers km 0 480 ma output 4 ma 0 160 ma output 4 ma Meters m 480 ma output 4 ma 160 ma output 4 ma Miles mi 0 298 ma output 4 ma 0 0993 ma output 4 ma Feet ft 1568 ma output 4 ma 522 7 ma output 4 ma Note It is very important to use the correct formula depending on what sensor visibility range and output voltage range was ordered Alternately the sensor output current may be converted to extinction coefficient as follows km K ma output 4 ma 1 6 where K is the calibration constant listed in Table 3 2 2 Then the extinction coefficient can be converted to visibility using MOR 3 0 where MOR is the meteorological optical range visibility and o is the extinction coefficient Note Remember that since the unit o
23. 0 0932 sensor 0 06213 sensor 0 0311 sensor output VDC output VDC output VDC output VDC Feet ft 984 sensor 492 sensor 328 sensor 164 sensor output VDC output VDC output VDC output VDC Note It is very important to use the correct formula depending on what sensor visibility range and output voltage range was ordered P N 80002 29 May 2007 Sentry Visibility Sensor User s Guide Alternately the sensor output voltage may be converted to extinction coefficient c as follows K sensor output voltage VDC where K is the calibration constant listed in Table 3 1 2 Then the extinction coefficient can be converted to visibility using MOR 3 0 where MOR is the meteorological optical range visibility and o is the extinction coefficient Note Remember that since the unit of measure of extinction coefficient is the calculated unit of measure of visibility is therefore kilometers To obtain the visibility in statute miles multiply the visibility in kilometers by 0 6412 Table 3 1 2 E Calibration Lower Visibility Range Output Range Constant K Voltage Limit 30m 16 km 0 10 VDC 10 0 01863 VDC 30m 16 km 0 5 VDC 20 0 00932 VDC 10m 10 km 0 10 VDC 30 0 010 VDC 10m 10 km 0 5 VDC 60 0 005 VDC Note The following paragraph describes the data processing algorithm that must be followed to insure proper operation of the Sentry over its operating range A simplifi
24. 0 326 mm or larger wire is recommended The cable run should be as short as possible 3 For the control relay 1 option Sensor P N SVS1 x C strip 6 mm 1 4 of insulation from each of the conductors and connect them to TB1 using the information in Table 2 3 3 1 and Figure 2 3 3 1 Note that the terminals marked with a prefix refer to the control relay output Table 2 3 3 1 TB1 Terminal Function 1 Normally Open 1 CNC1 Normally Closed NC 4 For the control relay 2 option Sensor P N SVS1 x E strip 6 mm 1 4 of insulation from each of the conductors and connect them to TB1 using the information in Table 2 3 3 2 and Figure 2 3 3 1 Note that the terminals marked with a prefix refer to the control relay output Table 2 3 3 2 TB1 Terminal Function CNO2 Normally Open NO 2 2 Normally Closed 5 For the diagnostic relay option Sensor P N SVS1 x D strip 6 mm 1 4 of insulation from each of the conductors and connect them to TB1 using the information in Table 2 3 3 3 and Figure 2 3 3 1 Note that the terminals marked with a D prefix refer to the diagnostic relay output Table 2 3 3 3 TB1 2 Terminal Function DNO Normally Open NO DCOM Common DNC Normally Closed NC P N 80002 23 May 2007 Sentry Visibility Sensor User s Guide 6 Tighten the cord grip to secure the signal cable 7 Connect the other end of th
25. 0027 Universal series switching power supply with short circuit overload amp over voltage protection The 50W supply provides 5 15 and 15 VDC power to the sensor electronics A green LED indicates power is applied AC Transformer P N 30014 Option Provides 24 VAC power to the optional hood heaters The transformer is only provided if the hood heater option is ordered Signal Processor PCB P N 30007 This PCB provides signal and DC power distribution to all sensor components The received signal from the RX PCB is demodulated using the synchronization pulses from the TX PCB After demodulation the signal is filtered through a low pass filter amplified and scaled to the appropriate level The output voltage passes through EMI filtering and surge protection before being made available to the user as an analog voltage or current The Signal processor also contains test points and an array of LEDs D1 that indicate sensor status In normal operation 3 of the LEDs are on continuously one is off or on based on connection of the optional 4 20 ma current loop and one LED is blinking approximately once every 2 seconds Additional information on the diagnostics and test points is contained in Section 5 Maintenance The analog output voltage or 4 20 ma output current is EMI filtered surge protected and available for user connections via an onboard terminal strip TB1 3 Relay Output Option PCB P N 30005 T
26. 20 ma single ended 2 3 2 SVS1 x B 4 20 ma isolated 2 3 2 SVS1 x C Control Relay 1 2 3 3 SVS1 x D Diagnostic Relay 2 3 3 SVS1 x E Control Relay 2 2 3 3 2 3 1 Analog Voltage Output Connection 1 Open the Main Electronics Enclosure by loosening the 2 captive screws on the bottom corners of the enclosure 2 Loosen the cord grip on the lower left bottom of the Main Electronics Enclosure 3 Feed a twisted shielded pair cable into the enclosure through the cord grip 22 AWG 0 326 mm or larger wire is recommended The maximum cable run should be 15 50 ft 4 Strip 6 mm 1 4 of insulation from each of the two conductors and connect them to Pins 1 and 2 of TB1 as shown in Table 2 3 1 1 and Figure 2 3 1 1 Table 2 3 1 1 TB1 Terminal Function 1 VDC Out 2 VDC Return 5 Tighten the cord grip to secure the signal cable 6 Connect the other end of the cable to the user s data acquisition equipment per the manufacturers instructions To reduce noise on the cable connect the cable shield to either signal ground or earth ground at the data acquisition system as required 7 Go to Section 2 4 for electrical power wiring instructions P N 80002 19 May 2007 Sentry Visibility Sensor User s Guide 9 9 a LZO w RB Lo a a LL 1 C C2 gt 2 C E som 2A o a9 aa 19 24 L o p P e ENT _ gt
27. 50 25 0 016 82 240 000 0 0125 13 0 008 41 3 0000 90 000 0 0333 33 0 021 109 180 000 0 0167 17 0 010 55 2 0000 60 000 0 0500 50 0 031 164 120 000 0 0250 25 0 016 82 1 0000 30 000 0 1000 100 0 062 328 60 000 0 0500 50 0 031 164 0 7500 22 500 0 1333 133 0 083 437 45 000 0 0667 67 0 041 219 0 5000 15 000 0 2000 200 0 124 656 30 000 0 1000 100 0 062 328 0 2500 7 500 0 4000 400 0 249 1312 15 000 0 2000 200 0 124 656 0 1000 3 000 1 0000 1000 0 621 3281 6 000 0 5000 500 0 311 1640 0 0500 1 500 2 0000 2000 1 243 6562 3 000 1 0000 1000 0 621 3281 0 0400 1 200 2 5000 2500 1 554 8202 2 400 1 2500 1250 0 777 4101 0 0300 0 900 3 3333 3333 2 071 10936 1 800 1 6667 1667 1 036 5468 0 0250 0 750 4 0000 4000 2 486 13123 1 500 2 0000 2000 1 243 6562 0 0200 0 600 5 0000 5000 3 107 16404 1 200 2 5000 2500 1 554 8202 0 0186 0 559 5 3677 5368 3 335 17610 1 418 2 6838 2684 1 668 8805 0 0150 0 450 6 6667 6667 4 143 21872 0 900 3 3333 3333 2 071 10936 0 0125 0 375 8 0000 8000 4 971 26246 0 750 4 0000 4000 2 486 13123 0 00932 0 280 10 7296 10730 6 667 35202 0 559 5 3648 5365 3 334 17601 0 01000 0 300 10 0000 10000 6 214 32808 0 600 5 0000 5000 3 107 16404 0 0080 0 480 6 2500 6250 3 884 20505 0 0060 0 360 8 3333 8333 5 178 27340 0 0050 0 300 1
28. Figure 2 1 2 1 Site Preparation Concrete Footer 17 Figure 2 1 2 2 Site Preparation Tower Boom 17 Figure 2 2 1 Mechanical Installation nnne nnne tinent 18 Figure 2 3 1 1 Analog Output Voltage 20 Figure 2 3 2 1 4 20 ma Current Loop Output Signal Connections eese 22 Figure 2 3 3 1 3 Relay Output Signal Connections 24 Figure 2 4 1 1 User AC Power 26 Figure 2 4 2 1 User DC Power enne nnne annnm nuit 27 Figure 2 4 3 1 Earth Grounding eese eene enne nnn Enean 28 Figure 3 3 1 3 Relay Control Relay Adjustment Points eese eene 38 Figure 4 0 1 P N 20004 Calibration 40 Figure 4 1 1 Calibration Test Points and Adjustment Points eese 41 Figure 4 1 2 Installation of ND4 Filter
29. Look before you reach under the hoods for wasp or beehives 6 Clean away any old spider webs that are on the sensor cross arm heads and enclosure 7 Spray the TX and RX lenses liberally with the window cleaner and wipe thoroughly with a soft clean cloth 8 If the power was turned off turn it back ON and observe the indicator lights per step 3 9 Close the Main Electronics Enclosure door and tighten the two 2 screws to secure the door Note About Spiders Spiders can be a problem at certain times of the year They may leave webs that cross the sensor s optical path causing inaccurate readings There appear to be no product available on the market today that will completely eliminate spider infestations The Tanglefoot Company 616 459 4139 or www tanglefoot com has a product called Tangle Guard Tree Care Kits that consists of a safe but sticky substance that is applied over a removable banding material The product can be applied to the sensor mounting pole cross arm and portions of the sensor heads Be aware that it is very messy and does not kill the spiders it only catches them if they cross a treated area P N 80002 47 May 2007 5 4 Corrective Maintenance 5 4 1 Initial Checks Sentry Visibility Sensor User s Guide TX SYNC Flashing ALM 1 Open the Main Electronics Enclosure by loosening the 2 captive screws on the cover 5 VDC 2 On AC versions observe that the green LEDs on
30. VDC if there is too much scattering of light into the receiver This may occur with either the 0 5 VDC or 0 10 VDC analog output options P N 80002 31 May 2007 Sentry Visibility Sensor User s Guide Table 3 1 3 SENTRY VISIBILITY SENSOR OUTPUT CURVE Standard 30m 16 Km Visibility Range 10 VDC Full Scale Output 5 VDC Full Scale Output Sentry EXCO MOR MOR MOR MOR EXCO MOR MOR MOR MOR Voltage 1 ft 1 ft 10 0000 100 000 0 0300 30 0 019 98 9 0000 90 000 0 0333 33 0 021 109 8 0000 80 000 0 0375 38 0 023 123 7 0000 70 000 0 0429 43 0 027 141 6 0000 60 000 0 0500 50 0 031 164 5 0000 50 000 0 0600 60 0 037 197 100 000 0 0300 30 0 019 98 4 0000 40 000 0 0750 75 0 047 246 80 000 0 0375 38 0 023 123 3 0000 30 000 0 1000 100 0 062 328 60 000 0 0500 50 0 031 164 2 0000 20 000 0 1500 150 0 093 492 40 000 0 0750 75 0 047 246 1 0000 10 000 0 3000 300 0 186 984 20 000 0 1500 150 0 093 492 0 7500 7 500 0 4000 400 0 249 1312 15 000 0 2000 200 0 124 656 0 5000 5 000 0 6000 600 0 373 1968 10 000 0 3000 300 0 186 984 0 2500 2 500 1 2000 1200 0 746 3937 5 000 0 6000 600 0 373 1968 0 1000 1 000 3 0000 3000 1 864 9842 2 000 1
31. a Figure 3 3 1 3 Relay Control Relay Adjustment Points 38 May 2007 Sentry Visibility Sensor User s Guide Control Relay 2 The customer must set the threshold of the control relay 2 Set this relay to the lower of the 2 control relay thresholds i e 1 km Figure 3 3 1 and the procedure steps below provide the details of setting up the control relay threshold 1 Select the visibility at which the control relay should activate Use the formulas in Section 3 1 and Table 3 1 1 for a 0 10 VDC output sensor to determine an equivalent sensor output voltage For example the equivalent sensor voltage for a threshold of 1 kilometers is calculated as follows Sensor VDC 0 300 1 km 0 300 VDC 30m 16 km standard visibility range Sensor VDC 0 100 1 km 0 100 VDC 10m 10 km optional visibility range 2 Connect a digital voltmeter DVM to TP2 and 3 Adjust R2 to set the threshold voltage to the voltage obtained above 4 To test the relay connect an ohmmeter to across the 2 and 2 terminals of TB1 5 Wave your hand in the Sentry sample volume to increase the sensor output and observe that the ohmmeter switches from open to short Diagnostic Relay Once the diagnostic relay is connected to the user system no further operation is required The diagnostic relay provides a basic indication of Sentry status If the relay activates the sensor has detected a prob
32. ade screwdriver loosen the blue and brown AC wires on the right side of the power supply Loosen the 2 screws that secure the AC Power Supply to the base plate Replacement Install and tighten the 2 screws that secure the new AC Power Supply to the base plate Plug the white 7 pin connector into J1 of the Signal Processor PCB Reinstall the base plate assembly into the enclosure and tighten the 4 corner screws securely Reconnect the green yellow ground wire from the Main Enclosure ground stud to the base plate ground stud Rewire the AC power input per Figures 5 4 2 2 and A1 as needed Rewire the user signal wires per Section 2 4 Calibrate the sensor per Section 4 before returning the Sentry to service DC Power Supply Turn AC or DC power OFF before proceeding with the removal and replacement instructions provided in this Section Removal Using a small flat blade screwdriver loosen the 2 DC input power wires from TB1 of the DC Power Supply PCB Unplug the white 7 pin connector from J1 on the right side of the Signal Processor PCB Using a small flat blade screwdriver unscrew the 4 corner screws that hold the DC Power Supply PCB to the base plate Carefully lift the PCB out of the enclosure Replacement Place the new DC Power Supply PCB over the base plate standoffs and replace the 4 screws and washers to secure it Plug the white 7 pin connector into J1 of the Signal Processor PCB Rewire the DC power input wires to TB1 per Se
33. ar If the sensor was off turn the sensor power and wait 10 minutes Connect a digital current meter with 4 1 digit resolution to the 4 20 ma output of TB1 of the Signal Processor PCB as shown in Figure 2 3 2 1 Install the Foam Light Block securely over the receiver optics by pushing it up under the hood and against the optics to completely block any incoming light The Light Block is concave so that it completely covers the protruding glass lens It is very important that the plug completely block out all incoming light Even very small amounts of stray light may cause the offset to be affected NOTE Never install the Scatter Plate during the zero check because the scattered signal is so intense that some of the light may reach the receiver If in doubt about the zero cover the transmitter and receiver heads with a cloth to verify that the zero stabilizes near 0 mV before proceeding Wait 3 minutes for the signal to stabilize Read the DVM and adjust R7 Zero Pot of the Signal Processing PCB to 4 000 Remove the Light Block and store it in the Attach Case OINI Install the ND4 Filter securely over the receiver optics by pushing it up under the hood and against the optics to completely block any incoming light Stretch the elastic cord around the back of the RX Head to hold the filter in place as shown in Figure 4 1 2 Install the Scatter Plate on the threaded studs on the back of the Ma
34. ard 0 5 VDC optional Sentry Visibility Sensor User s Guide Sentry Specifications 30 m 16 km 10m 10 km optional 100 0 1863 km 300 0 30 km optional 10 60 42 deg nominal 880 nm LED 100 240 VAC 50 60 Hz 24 VA 75 VA w Hood Heaters 10 36 VDC 6 VA nominal 18 VA w Hood Heaters with remote power down for critical power applications 8 kg 18 Ib nominal 889 mm W x 292 mm H x 305 mm D 35 in x 11 5 in x 12 in Nominal 40 mm pipe 48 3 mm OD max 1 1 2 inch IPS pipe 1 9 inch OD max Optional 25 mm pipe 33 mm OD max 1 inch IPS pipe 1 3 OD max 40 to 60 C 0 100 66 4 4 20 ma single ended optional 4 20 ma isolated optional Control Relay 1 optional Control Relay 2 optional Latching Relay optional Diagnostic relay optional The following section describes additional options and accessories that are available for the analog output Sentry P N 80002 3 May 2007 Sentry Visibility Sensor User s Guide 1 2 1 Description of Options amp Accessories The part number P N of the Sentry is key to understanding what options are installed each unit The P N is found on the sensor label shown in Figure 1 2 1 1 which is located on the outside of the Main Electronics Enclosure The P N is composed of 2 parts The first 4 characters indicate the model example SVS1 followed by options characters xx y H P Each of the options characters identif
35. ate and ND4 Filter return all parts to the Attach Case 16 Disconnect the current meter from TB1 of the Signal Processor PCB and reconnect the current loop wiring to the user equipment 17 Close and secure the door of the Main Electronics Enclosure P N 80002 45 May 2007 Sentry Visibility Sensor User s Guide 5 0 Maintenance 5 1 EnviroTech Sensor Inc Product Warranty Warranty EnviroTech Sensors Inc Seller warrants its products to be free of defects in material and workmanship under normal conditions for a period of eighteen 18 months from date of shipment subject to the following Warranty does not apply to products that have been subject to mishandling misapplication modification abuse neglect accident of nature or shipping damage e The Seller is not liable for incidental or consequential damage caused by its products including but not limited to damages for loss of use income profit or good will losses sustained as a result of death or injury to any persons and or damages to property other than the product In no case shall the Seller s liability exceed the price paid for the product This warranty is expressly in lieu of any other expressed or implied warranty of merchantability or fitness for a particular purpose and of any obligations or liabilities on the part of the Seller or its employees or agents 5 2 Correcting Defects Under the
36. ction 2 3 2 Calibrate the sensor per Section 4 before returning the Sentry to service P N 80002 53 May 2007 Sentry Visibility Sensor User s Guide Output Option PCB Turn AC or DC power OFF before proceeding with the removal and replacement instructions provided in this Section e Removal Using a small flat blade screwdriver loosen the 2 signal wires from TB1 and or TB2 of the Output Option PCB Carefully slide the PCB out of the card guides of the Signal Processor PCB e Replacement Place the new Output Option PCB into the card guides of the Signal Processor PCB and carefully seat the mating connectors Rewire the user signal wires to TB1 and or TB2 per Section 2 4 2 Calibrate the sensor per Section 4 before returning the Sentry to service 5 5 Field Replaceable Units FRU s Only certain parts of the Sentry may be replaced in the field The TX and RX Heads are not field repairable and should not be opened The Signal Processor PCB in the Main Electronics Enclosure is not field replaceable without factory training Table 5 5 1 provides a list of the field replaceable units Contact Enviro Tech Sensors for information about what FRUs are applicable to your Sentry Table 5 5 1 FRU Description FRU P N AC Surge Protection Module 70004 Switching AC Power Supply Assy 30027 DC Power Supply Assy 30006 Signal Processor 9 30007 3 Relay Output Option 30005 xxx AC External Hood Heater Trans
37. der In most operating environments quarterly 120 day maintenance is recommended Calibration as described in Section 4 is performed every six 6 months Each user should select the maintenance frequency that meets their needs In some road weather applications where the sensor is exposed to wet dirty spray from passing vehicles it may be necessary to clean the optics more frequently Remember that the sensor output data will be incorrect during the maintenance activities Either turn the sensor power off or record the date and time of the maintenance for later reference Equipment Needed e cloth Hazardous voltage Window cleaning solution reris 2 hand tools may this equipment Procedure 1 Using a straight blade screwdriver loosen the two 2 screws that secure the door on the Main Electronics Enclosure 2 On AC powered units observe that the green LEDs on the surge protection module and AC power supply are lit On DC powered units follow step 3 3 Observe that the first three 3 green LEDs are lit on D1 of the Signal Processor PCB Observe that the last LED is blinking at approximately 1 Hz once per second Refer to Figure 5 4 1 1 4 Use caution when following the steps below If it is below 5 C 40 F the external hood heaters may be HOT Turn sensor power off before proceeding 5 Using the soft cloth clean the area under the TX and TX hoods
38. e are a Receiver PCB PIN photodiode optical lens with heater and mounting brackets There are no user serviceable parts in the RX Head WARNING Opening the RX Head will void the warranty of the sensor Main Electronics Enclosure Externally the Main Enclosure consists of a weatherproof enclosure with hinged door for easy access A mounting flange is attached to the bottom of the Enclosure for attachment to a support pole of 40 mm dia 1 7 Schedule 40 pipe A mounting plate is attached to the backside of the Enclosure for use in calibrating the sensor not shown in Figure 1 3 1 The internal components are discussed in the next section P N 80002 8 May 2007 Sentry Visibility Sensor User s Guide Crossarm TX Weldment Mounting Flange 40 mm Mounting Pipe Customer provided Optional Items Figure 1 3 1 Sentry Major Components P N 80002 9 May 2007 Sentry Visibility Sensor User s Guide Power Version See Table 1 3 2 and Figure 1 3 2 below Table 1 3 2 Internal Components of the Main Enclosure Description and Function Surge Protection Module P N 70004 Provides AC surge protection EMI filtering and short circuit protection The user makes AC power connections directly to this module using the built in terminal strip A green LED on the module is illuminated when AC power is applied to the sensor and the module is working normally AC Power Supply P N 3
39. e cable to the users data acquisition equipment per the manufacturers instructions To reduce noise on the cable connect the cable shield to either signal ground or earth ground at the data acquisition system 8 Goto Section 2 4 for electrical power wiring instructions ENVRDTECH SENSORS INC 5 me 5 y Control Relay 1 Control Relay 2 Diagnostic Relay 99 49 2 Figure 2 3 3 1 3 Relay Output Signal Connections P N 80002 24 May 2007 Sentry Visibility Sensor User s Guide 2 4 Electrical Power Installation The most important step in connecting power to the Sentry is to make sure only authorized personnel make the AC connections Read the information in Section 2 of this User s Guide completely before proceeding Remember that local electrical codes supersede the recommendations provided herein Hazardous voltage inside Only authorized If you have a question call EnviroTech Sensors Inc this gt at 410 531 8596 The second step in connecting power to the Sentry is to make sure the correct mains voltage is used Read the product label on the outside of the Main Electronics Enclosure door and compare the part number in Table 2 4 1 as follows Table 2 4 1 MyourP Nis Thenyourmainsis Seesection 1 110 240 VAC 50 60 Hz 24 1 1 0 10 36 VDC 2 4 2 For protection from lightning and other elect
40. ed data processing algorithm is provided as guidance Read sensor output voltage every few seconds e Limit the sensor output to the full scale range using an IF THEN type logic statement IF the sensor output voltage is lt the value shown THEN set the sensor voltage to the value shown in Table 3 1 2 above Else set the voltage reading to actual reading e Convert to visibility in correct units of measure using formulas provided e Compute running average of 3 5 minutes Archive averaged data once per minute As an example 1 If the sensor voltage 0 0150 for a 16 km visibility range with 0 10 VDC analog output 0 0150 VDC 0 01863 VDO then set the voltage to 0 01863 VDC 10 miles or 16 km P N 80002 30 May 2007 Sentry Visibility Sensor User s Guide 2 If the sensor voltage 0 0220 VDC for a 16 km visibility range with 0 10 VDC analog output 0 0220 VDC 0 01863 VDO then set the value to the measured voltage of 0 0220 VDC and calculate the visibility as 0 1864 0 0220 8 47 miles or 13 9 km Table 3 1 3 below shows the relationship between sensor voltage extinction coefficient EXCO and equivalent MOR visibility in kilometers meters statute miles and feet for the standard 30m 16 km visibility range with 0 10 VDC and 0 5 VDC voltage outputs Table 3 1 4 repeats this information for the optional 10m 10 km visibility range Note The Sentry output voltage may saturate at gt 10
41. ensor data over long cables The standard 4 20 ma option uses a single Optional Optional ended configuration Operates over total loop resistances of up to 500 ohms SPDT relays provide normally open NO and normally closed NC contacts and are rated at 100 VDC 0 25A Diagnostic Relay Diagnostic Relay Output provides remote indication of sensor status The relay is continuously activated and will deactivate if a 4 20 ma isolated an industry standard method of transmitting the sensor data over long cables isolated 4 20 ma option is for installations prone to severe ground loops Operates over total loop resistances of up complete power failure occurs or when any of 4 diagnostic tests fail It checks 5 12 VDC 12 VDC and transmitter sync for proper EM EN to 500 ohms Control Relay 1 Control Relay Output provides user adjustable visibility threshold to activate a relay This option allows simple control of C Optional Optional operation The SPDT relays provide normally open NO and normally closed NC contacts and are rated at 100 VDC 0 25A Control Relay 2 Control Relay Output provides user adjustable visibility threshold to activate a relay This option allows simple control of warning E Optional lights foghorns gate closures and other indication devices The SPDT warning lights foghorns gate closures and other indication devices The relays provide normally open NO and normally
42. ers data acquisition equipment per the manufacturers instructions To reduce noise on the cable connect the cable shield to either signal ground or earth ground at the data acquisition system as required Go to Section 2 4 for electrical power wiring instructions P N 80002 21 May 2007 Sentry Visibility Sensor User s Guide p o RB Lo a o uy C2 2A o a9 aa 19 pi L 5 p P e ENT _ gt Fo le EMT cis RT T C6 E o UB D C26 1 4 ler g 1 STD oo 50 J4 x H ENVIRQTECH SENSORS INC ASSY 30007 S N D ma Out ma Return Figure 2 3 2 1 4 20 ma Current Loop Output Signal Connections P N 80002 22 May 2007 Sentry Visibility Sensor User s Guide 2 3 3 3 Output Connection for P N 30005 xxx The Sentry relay options are part of an auxiliary PCB that plugs into the Signal Processor PCB in the Main Electronics Enclosure User connections are made to TB1 of the P N 30005 xxx 3 Relay PCB depending on what options were ordered 1 Loosen the cord grip on the lower left bottom of the Main Electronics Enclosure 2 Depending on the number of relays to be wired feed a 1 2 or 3 twisted shielded pair cable into the enclosure through the cord grip 22 AWG
43. ew module over the DIN rail with the protected side on the right Clip the left side over the left side of the DIN rail and lower the right side until it clips on the rail Slide the lower DIN rail clamp up against the new module and tighten its hold down screw to secure the surge module Wire the module per Figure 5 4 4 1 and refer to Section 2 3 1 for additional information Calibrate the sensor per Section 4 before returning the Sentry to service um GR YL BL BR User Supplied Sensor Internal AC Wiring AC Wiring Figure 5 4 4 1 Surge Module Wiring P N 80002 52 May 2007 Sentry Visibility Sensor User s Guide AC Power Supply Turn AC or DC power OFF before proceeding with the removal and replacement instructions provided in this Section Removal Disconnect the signal wiring from TB1 terminal board on the Signal Processor PCB or output option board if installed Using a small flat blade screwdriver loosen the 3 AC input wires on the left side of the surge module Using a 3 8 nut driver loosen the hex nut on the 10 32 ground screw located in the lower right corner of the base plate Lift off the green yellow wire that connects to the Main Enclosure 4 20 ground stud Using a long flat blade screwdriver unscrew the 4 white base plate corner screws Carefully tip the base plate assembly out of the enclosure Unplug the white 7 pin connector from J1 on the right side of the Signal Processor PCB Using a small flat bl
44. f measure of extinction coefficient is the calculated unit of measure of visibility is therefore kilometers To obtain the visibility in statute miles multiply the visibility in kilometers by 0 6412 P N 80002 34 May 2007 Sentry Visibility Sensor User s Guide Table 3 2 2 Calibration Lower Visibility Range Output Range Constant K Current Limit 30m 16 km 4 20 ma 10 4 030 ma 10m 10 km 4 20 ma 30 4 016 ma As shown in Figure 5 4 1 1 a green LED 04 is provided on the Signal Processor PCB that provides an alarm indication of whether the 4 20 ma loop is connected and within voltage limits In normal operation with a complete connection to the user s data acquisition equipment the ALM LED should be OFF If the LED is ON check for correct wiring connections Note The following paragraph describes the data processing algorithm that must be followed to insure proper operation of the Sentry over its operating range A simplified data processing algorithm is provided as guidance Read sensor output voltage every few seconds e Limit the sensor output to the full scale range using an IF THEN type logic statement F the sensor output voltage is the value shown THEN set the sensor voltage to the value shown in Table 3 2 2 above Else set the voltage reading to actual reading e Convert to visibility in correct units of measure using formulas provided e Compute running average of 3 5 minutes e
45. f two ways attached to an existing structure such has a meteorological tower or as a stand alone installation In either case provisions must be made for physically supporting the structure earth grounding power and signal wiring 40 mm pipe inch Sch 40 0 3 m 12 inch e Support Structure If the sensor is to be installed as a stand alone instrument prepare a concrete footer as shown in Figure 2 1 2 1 It is recommended that depth of the concrete Concrete 0 2 3 feet footer is below the frost line to avoid heaving When preparing for the concrete footer also or gravel plan for earth grounding power wiring and Y signal wiring Figure 2 1 2 1 Site Preparation Concrete Footer e The Sentry may also be installed on an existing structure such as a triangular tower using a boom arm structure The boom arm should extend at least 1 m 3 ft out from the side of the tower to reduce water or snow dripping from the upper portions of the tower into the sensing volume of the sensor The boom arm may be made from 1 inch or 1 gt inch Schedule 40 pipe as shown in Figure 2 1 2 2 Check your sensor model number if it ends in your sensor is equipped with a 1 nominal pipe flange and you must use 1 inch pipe for the mounting arm Otherwise use 1 1 2 pipe The boom arm structure should be attached to the side of the triangular tower with U bolts or similar hardware
46. for applications where high winds or long mounting poles boom arms are used to reduce sway and vibration P 1 inch flange Optional flange mount where small pipe is required blank 1 1 2 flange P N 80002 6 May 2007 Sentry Visibility Sensor User s Guide 1 2 1 5 Accessories Several accessories are available with the Sentry as described in Table 1 2 1 6 1 Table 1 2 1 6 1 Part Accessory Required for installation maintenance of the sensor When installed on the sensor frame it allows a known amount of light to be scattered from the transmitter to the receiver One Calibration Fixture can be used on several Sentry Visibility Sensors Calibration P N 20004 Fixture Latching P N 30100 Relay AC Power P N 70009 Cable P N 70010 Signal Cable P N 70011 DC Power Xx Cable Provides a latching relay output that maintains the control relay state during power failures or battery savings power down cycles Must be used with either or E control relay options described above Normally open NO dry contacts rated for 30 or 125 1 Optional North American style 3 conductor 18 AWG 3 meter molded male plug SJT type UL amp CSA rated CEE color codes Power cables for international orders will be supplied with the appropriate molded plug Optional twisted shielded pair cable 22 AWG PVC jacket where is
47. former 30014 Note1 You must order the exact P N replacement see your PCB for complete part number 5 6 Training Additional training is available from EnviroTech Sensors Inc Custom courses are offered in such areas as visibility theory and practice siting guidelines and installation amp maintenance These training courses are available at the EnviroTech Sensors Inc factory at the user s facility or in the field Contact EnviroTech Sensors Inc for more information Training is recommended for the user to become an authorized and knowledgeable service person P N 80002 54 May 2007 Sentry Visibility Sensor User s Guide Appendix P N 80002 55 May 2007 Sentry Visibility Sensor User s Guide 2002 02 5 5 5 jou 93 8000 Nid 0107 1650 96658 16001 S10suag Inq A 9 WOO Pue WOO 6 5 eiqun vVOLZ GW dy 1o0suesg Aji iqisi PY 55801 S MIGISIA 5 105095 ue Loug unie Ov punog wney J0A SOA 2 A IX 07 0 00 20 38 42006 Nid 90006 Nid gm Alddns 82d i H3MOd OV indino 2 Hr S onsouDerg 4000 e
48. his PCB plugs into the circuit card guides provided on the Signal Processor PCB and provides up to 3 relay outputs that may be ordered with the sensor The PCB receives power and signals from the Signal Processor PCB Two control relays and one diagnostic relay are available See Section 1 2 1 3 for additional information on the output options P N 80002 10 May 2007 Sentry Visibility Sensor User s Guide P N 30007 Signal Processor PCB P N 30005 CDE P N 30027 3 Relay Power Optional Supply TB1 Anal Mie AC Power Connection 70004 Protection Module Figure 1 3 2 Main Enclosure Components AC Power Version P N 80002 11 May 2007 Sentry Visibility Sensor User s Guide DC Power Version See Table 1 3 3 and Figure 1 3 3 below Table 1 3 3 Internal Components of the Main Enclosure Description and Function DC Power Supply P N 30006 The DC DC Converter Module provides 5 15 and 15 VDC power to the sensor electronics Also provides DC surge protection EMI filtering and short circuit protection via resettable fuses The user makes DC power connections directly to this PCB using the built in terminal board TB1 The user connects a regulated DC voltage between 10 36 VDC capable of supplying 1A An added feature is the ability to remotely turn power OFF to the Sentry to reduce power consumption By connecting a ground to terminal 3
49. ies a specific option on the unit mains voltage options y log output options Sensors Inc We eue Clarksville MD 21029 USA jos hood heaters Sentry Visibility Sensor e pipe mount flange E 5 5 Figure 1 2 1 1 Sensor Label 1 2 1 1 Power Supply Options The 1 option character group describes the mains voltage options on the Sentry as described in Table 1 2 1 1 1 Table 1 2 1 1 1 When the 1 Then the Standard Description characters Mains or Voltage Nominal Power Power w are Voltage is Optional Range w o HTRS HTRS te 100 240 Standard 88 264 47 63 Hz 24 VA 75 VA 12VDC Optional 1036VDC 18VA Note 1 See Section 1 2 1 3 for information on the external hood heater option P N 80002 4 May 2007 Sentry Visibility Sensor User s Guide 1 2 1 2 Analog Options The 274 option character group describes the analog output options on the Sentry as described in Table 1 2 1 2 1 When the 27 Optional or character is Standard Table 1 2 1 2 1 This output provides 0 10 VDC full scale analog voltage provides the best analog resolution The output impedance is 50 ohms 0 5 VDC full scale analog voltage provides a reduced analog resolution that may be necessary for some data acquisitions systems The output impedance is 50 ohms 4 20 ma single ended an industry standard method of transmitting the s
50. in Electronics Enclosure using the thumbnuts supplied in the P N 20004 Calibration Fixture as shown in Figure 4 1 3 Note the Scatter Plate orientation The Plate installs with the 2 circular mounting hole on the top stud and the slot the bottom stud When installed correctly the top of the plate will be flush with the top of the sensor cross arm 11 Wait 3 minutes for the signal to stabilize P N 80002 44 May 2007 Sentry Visibility Sensor User s Guide 12 Record the EXCO written on the Calibration Fixture km 13 Compute the equivalent sensor calibration current from the EXCO above as follows Standard Visibility Range of 30m 16 km Sensor Cal Current EXCO 0 16 4ma ma Example If Cal Fixture EXCO 42 5 km expected current is as follows 42 5 0 16 4 ma 6 8 ma amp 4 ma 10 8 Optional Visibility Range of 10m 10 km Sensor Cal Current EXCO 0 0533 4 ma e OIH Example If Cal Fixture EXCO 42 5 km expected current is as follows 42 5 0 0533 4 ma 2 27 ma amp 4 ma 6 27 ma Remember that the visibility range of the Sentry is usually 16 km If the range is the optional 10 km it will be marked on the inside of the Main Electronics Enclosure 14 Read the current meter and adjust R17 Span Pot of the Signal Processing PCB to the calculated calibration current recorded in Step 13 15 Remove the Scatter Pl
51. ith high voltage are clearly Only authorized marked with the following label Verify that AC power is OFF before la proceeding with installation and maintenance of the sensor If you have a Ee question please call us at 410 531 8596 P N 80002 iv May 2007 Sentry Visibility Sensor User s Guide 1 0 Introduction Visibility is the term commonly used to express how far a person can see But the question is actually quite complicated due to the complex psychological and physical nature of the measurement As reported by the World Meteorological Organization WMO any visual estimate of visibility is subjective Visibility better known as meteorological optical range is the greatest distance that a large dark object can be seen and recognized against a light sky background Questions often arise as to the size and color of the object or target The object must be large subtend an angle of 20 5 degrees Depending on the distance from the observer a white church steeple that is 4 feet wide and 1000 feet away is an unacceptable target since it only subtends an angle of 0 2 degrees and is the wrong color A light pole that is only 1 foot in diameter is an even worse choice as a target Some of the other factors that affect a humans ability to measure visibility are the ambient light level the persons corrected vision and the training of that person to be a qualified weather observer Even with all these factors equal bet
52. l more accurately reflect what the DA system is measuring A 1 mV offset can cause a large difference at the 10 mile full scale output of the Sentry If unable to connect to the data acquisition system inputs connect to TP9 and TP2 of the Signal Processing PCB as shown in Figure 4 1 1 Pot TP2 Ground 3 Figure 4 1 1 Calibration Test Points and Adjustment Points Install the Foam Light Block securely over the receiver optics by pushing it up under the hood and against the optics to completely block any incoming light The Light Block is concave so that it completely covers the protruding glass lens It is very important that the plug completely block out all incoming light Even very small amounts of stray light may cause the offset to be affected NOTE Never install the Scatter Plate during the zero check because the scattered signal is so intense that some of the light may reach the receiver If in doubt about the zero cover the transmitter and receiver heads with a cloth to verify that the zero stabilizes near 0 mV before proceeding P N 80002 41 May 2007 Sentry Visibility Sensor User s Guide 6 Wait 3 minutes for the signal to stabilize 7 Read the DVM and adjust R7 Zero Pot of the Signal Processing PCB to 0 0 0 5 mV 8 Remove the Foam Light Block and store it in the Attach Case 9 Ins
53. lem with DC input power sensor derived voltages or transmitter function See Section 5 4 for assistance on corrective maintenance Note For applications used to control foghorn or warning lights it is recommended that the user supplied control system activate only after sensing several continuous minutes of activated relay closure from the Sentry sensor This will prevent momentary inadvertent activations of the warning system P N 80002 39 May 2007 Sentry Visibility Sensor User s Guide 4 0 Calibration The Sentry is initially calibrated at the factory using a standard Calibraton Fixture It is recommended that the calibration be checked during the field installation and every 6 months afterward The calibration procedure should be performed when the visibility is 21 2 mile with no precipitation The P N 20004 Calibration Fixture shown in Figure 4 0 1 is used to check the sensor calibration The Calibration Fixture consists of portable Attach Case with 1 Foam Light Block for checking the sensor zero 2 Neutral Density ND4 Filter for checking the sensor span 3 Scatter Plate used in conjunction with the ND Filter for checking the sensor span and 4 thumb nuts for attaching the Scatter Plate to the mounting studs on the back of the Main Electronics Enclosure Three 3 thumbnuts are provided 2 for use to hold the Scatter Plate and 1 as a spare 14 20 hex nut can also be used but the thumbnuts are easier to use a
54. lows Table 3 0 1 If your P N is Then your output is See section SVS1 x 1 0 10 VDC analog 3 1 SVS1 x 2 0 5 VDC analog 3 1 SVS1 x A 4 20 ma single ended 3 2 SVS1 x B 4 20 ma isolated 3 2 SVS1 x C Control Relay 1 3 3 SVS1 x D Diagnostic Relay 3 3 SVS1 Xx E Control Relay 2 3 3 3 1 Analog Voltage Output The standard Sentry visibility measurement range is 30m 16 km with an output voltage range of 0 10 VDC or 0 5 VDC as optional The alternate Sentry visibility measurement range is 10m 10 km with an output voltage range of 0 10 VDC or 0 5 VDC as optional Unless special ordered the Sentry is supplied with the 16 km visibility range On special order the Sentry is supplied with a 10 km range and this will be noted on the inside of the Main Electronics Enclosure The sensor analog output voltage must be converted to extinction coefficient c or visibility MOR in the appropriate units of measure Most users should convert directly from voltage to visibility using one of the formulas in Table 3 1 1 Table 3 1 1 30m 16 km Range 10m 10 km Range Visibility Units 0 10 VDC of Measure Output 0 5 VDC Output 0 10 VDC Output 0 5 VDC Output 0 300 0 150 sensor 0 100 sensor 0 050 sensor Kilometer kim output VDC output VDC output VDC output VDC Meters m 300 sensor 150 sensor 100 sensor 50 sensor output VDC output VDC output VDC output VDC Miles mi 0 1864 sensor
55. nd require tools The Calibration Fixture is assigned a factory traceable extinction coefficient EXCO that is recorded on the ND4 Filter and the Scatter Plate Equipment Needed P N 20004 Calibration Fixture Clean cloth Window cleaning solution Common hand tools Foam Lined Attache Case Drawstring Bag with 3 Thumb Nuts Scatter Plate Figure 4 0 1 P N 20004 Calibration Fixture For analog output voltage sensors go to Section 4 1 For 4 20 ma current output sensors go to Section 4 2 P N 80002 40 May 2007 4 1 Sentry Visibility Sensor User s Guide Procedure for Calibrating the Analog Voltage Output Sentry Sensor Note This procedure may be used for the 0 5 VDC and 0 10 VDC analog outputs Step Procedure 1 Inspect the Scatter Plate and ND4 Filter to insure they are clean free of scratches mechanically sound and have matching serial numbers If you are uncertain about the integrity of the Calibration Fixture contact EnviroTech Sensors for information about returning it for service Clean the sensor windows with common window cleaner and remove any insect nests spider webs or other debris under the hoods to ensure that the optical path is clear If the sensor was off turn the sensor power ON and wait at least 15 minutes Connect a digital voltmeter DVM with 4 gt digit resolution to the inputs of the customer data acquisition DA system Connecting at the DA system wil
56. ount of light detected by the receiver also increases In other words the received signal strength is inversely proportional to the visibility Sample Volume 42 Deg Forward Scatter Angle RX TX Figure 1 1 1 Forward Scatter Geometry 1 2 Specifications of the Sentry Performance in all weather conditions was a design requirement for the Sentry integrated one piece housing design keeps all cabling internal to the sensor for the ultimate protection against the elements The sensor housing is made from anodized aluminum and the enclosures are rugged UV resistant fiberglass and environmentally rated to IP66 Based on the proven experience of the NWS and FAA the sensor uses look down geometry to reduce window contamination and clogging from blowing snow The windows use continuous duty anti dew heaters and optional thermostatically controlled external hood heaters for protection in cold amp snowy weather conditions All power and signal lines to the Sentry are protected with surge and EMI filtering to help guarantee uninterrupted service for the life of the sensor Detailed specifications are included below P N 80002 2 May 2007 Performance e Visibility Range Extinction Range Accuracy Time Constant Scatter Angle Source Power e AC Version e DC Version Physical e Weight e Dimensions Mounting Environmental e Temperature Humidity e Protection Outputs e 0 10 VDC stand
57. re 2 1 1 1 Sensor Orientation For installations in road weather information systems RWIS special conditions may apply Do not locate the sensor on the top of a hill or bottom of a basin unless you wish to measure the visibility in that limited area as may be required for road weather applications e Do not locate the sensor too near a roadway to avoid the wet dirty plumes from passing vehicles that may contaminate the sensor optics e If the installation must be near the edge of the road it may be best to orient the sensor parallel to the road with the Main Electronics Enclosure facing the roadway as shown in Figure 2 1 1 2 P N 80002 15 May 2007 Federal Highway Administration FHWA has established standards for RWIS systems siting Contact FHWA and request Publication No FHWA HOP 05 206 or visit http ops fhwa dot gov publications ess05 index htm e The World Meteorological Organization WMO has published Report No 61 Road Meteorological Observations that also recommends sensor siting Contact the WMO and request TD 842 IOM 61 or http www wmo int pages prog www IMOP publication s lIOM series html For installations in road or rail tunnels the user is encouraged to visit the EnviroTech web link http www envirotechsensors com PDF Tunnel 20Guidelines pdf to obtain the Tunnel Guidelines document It contains information on visibility sensor siting recommendations within the tunnel specifics about in
58. rical surges the sensor should be grounded to a rod driven into the ground adjacent to the sensor per Section 2 4 3 Equipment required 14 inch straight blade screwdriver Small screwdriver Wire cutters Wire strippers Adjustable wrench 7 16 inch wrench 7 16 inch nut driver or adjustable wrench 2 4 1 AC Power Connections 1 If a North American style AC power cord P N 70009 was ordered with the sensor a 3 m 9 ft power cord is already installed Connect the molded AC plug into an approved 3 prong outlet 2 A weatherproof outlet cover as shown in Section 2 1 2 is recommended 3 Go to Section 2 4 3 for earth grounding the Sentry 4 lf you will be wiring the sensor with your own AC power cable loosen the cord grip on the lower right bottom of the Main Electronics Enclosure 5 Feed the power cable into the enclosure through the cord grip Strip 6 mm 1 4 of insulation from each of the three conductors and connect them to the line left side of the Surge Protection Module as shown per Table 2 4 1 1 and in Figure 2 4 1 1 P N 80002 25 May 2007 Sentry Visibility Sensor User s Guide Table 2 4 1 1 International ICC E dd Surge Module Colors Colors Terminal Green Yellow J E earth ground Noaoa C Bow Bak User Supplied AC Wiring Figure 2 4 1 1 User AC Power Wiring 6 Tighten the cord grip to secure the power cord 7 Go to Section 2 4 3 for earth gro
59. rom the Signal Processor PCB Two control relays and one diagnostic relay are available See Section 1 2 1 3 for additional information on the output options P N 80002 12 May 2007 Sentry Visibility Sensor User s Guide P N 30006 DC P N 30007 Signal Power Supply Processor PCB PCB TB1 Analog TB1 Output DC Power Connection Connection Earth Ground Figure 1 3 3 Main Enclosure Components DC Power Version P N 80002 13 May 2007 Sentry Visibility Sensor User s Guide 1 4 Signal Flow Sentry is an electro optic instrument based on the proven forward scatter technique The signal flow diagram in Figure 1 4 1 below illustrates the sensor functionality The TX Head consists of both electrical and optical subassemblies The TX PCB contains a frequency source modulator power amplifier phase shifter temperature compensator and high power LED The IR light from an LED is beam formed by an optical lens and projected into the sample volume where it encounters airborne particulate matter A synchronization pulse is sent from the TX PCB to the Signal Processor PCB to synchronize the demodulation of the received signal The power and signal cable from the TX Head terminates at J3 on the Signal Processor PCB in the Main Electronics Enclosure Light is scattered from the particulate matter in the sample volume in a forward direction and detected by the RX Head A lens focuses the received IR light onto a sensitive photo detec
60. s for all users e Use a sturdy pole or pedestal to reduce vibration e Locate the sensor an area that is representative of the area to be monitored Do notlocate the sensor near strobe lights and other modulated light sources Do notlocate the sensor in an area that is subject to localized sources of smoke fog or mist air handling exhausts smoke stacks etc unless you are trying to measure the reduction in visibility from these sources e The area within 5 6 meters 16 20 feet of the sensor should be free of all vegetation over 25 cm 10 inch and well drained e Avoid any vertical objects such as hills walls or plants within this area o lfin path of the TX beam light may be reflected back into the receiver giving false readings o lfin path of RX beam stray sunlight may be reflected back into the receiver giving false readings e Mount the sensor so the optics are at least 2 5 3 meters 8 10 feet above ground or 2 5 meters 8 feet above the average maximum snow depth whichever is higher e n general orient the sensor receiver optics so they face within 30 degrees of North in the Northern hemisphere or South in the Southern hemisphere to eliminate direct sunlight contamination Figure 2 1 1 1 shows the correct orientation in the Northern Hemisphere In the southern Hemisphere rotate the sensor 180 degrees Note the orientation is not critical it may be adjusted to fit the needs of the installation Figu
61. stalling the Sentry and guidance information about how several agencies around the world are using the data from tunnel mounted visibility sensors A typical tunnel installation is shown in Figure 2 1 1 3 Sentry Visibility Sensor User s Guide Figure 2 1 1 2 Typical Roadside Installation Tunnel Cutaway End View Ventilation Fans 0 6 Sentry Sensor Railing Road Bed Walkway Figure 2 1 1 3 Typical Tunnel Installation For installations at airports the user is encouraged to contact one of the regulating agencies to ensure compliance with aviation requirements e U S A Office of the Federal Coordinator for Meteorology at 301 427 2002 Silver Spring Maryland for a copy of Federal Standard for Siting Meteorological Sensors at Airports OFCM FCM S4 1994 and other related documents or visit http www ofcm gov siting text a cover htm e International International Civil Aviation Organization at 514 954 8022 Montreal Quebec Canada for a copy of Manual of Aeronautical Meteorological Practice and other related documents Or visit http www icao int icao en sales htm P N 80002 16 May 2007 Sentry Visibility Sensor User s Guide 2 1 2 Site Preparation The selected site must be prepared in accordance with local construction codes and therefore the information provided in this section is for guidance only The Sentry is typically installed in one o
62. tall the ND4 Filter securely over the receiver optics by pushing it up under the hood and against the optics to completely block any incoming light Stretch the elastic cord around the back of the RX Head to hold the filter in place as shown in Figure 4 1 2 Figure 4 1 2 Installation of NDA Filter 10 Install the Scatter Plate on the threaded studs on the back of the Main Electronics Enclosure using the thumbnuts supplied in the P N 20004 Calibration Fixture as shown in Figure 4 1 3 Note the Scatter Plate orientation The Plate installs with the 1 4 circular mounting hole on the top stud and the slot on the bottom stud When installed correctly the top of the plate will be flush with the top of the sensor cross arm md Scatter Plate Top of Scatter Plate Level with Top of Sensor Cross Arm Thumb Screw 2 PLCS Figure 4 1 3 Installing the Scatter Plate 11 Wait 3 minutes for the signal to stabilize 12 Record the EXCO written on the Calibration Fixture km P N 80002 42 May 2007 Sentry Visibility Sensor User s Guide 13 Compute the equivalent sensor calibration voltage from the EXCO above as follows Standard Visibility Range of 30m 16 e For 10 VDC full scale output sensors with P N SVS1 x 1 Sensor Cal Voltage EXCO 10 VDC e For 5 VDC full scale output sensors with P N SVS1 x 2 Sensor Cal Voltage EXCO 20 VDC Optional Visibility Range of 10m 10 km e For 10 VDC f
63. tection initiatives by the European Union known in the industry as WEEE and RoHS Effective 1 January 2006 our company and products will comply with the WEEE directive 2002 96 EC We are currently exempt from RoHS requirements because our products broadly fall under Annex 1A Section 9 Monitoring and Control Instruments Despite our current exempt status we are actively moving towards RoHS compliance P N 80002 i May 2007 Table of Contents 1202 Arodu i 1 2 1 2 Specifications of the SentryTM 2 1 2 1 Description of Options amp 4 1 2 1 1 Power Supply Options cia ie 4 1 2 1 2 Analod ODHODS 5 1 2 1 3 Hood Heater oeste ipe Ei ees 6 1 2 1 4 Mounting Flange ODONIS o eec Dein 6 1 2 1 5 PCCOS SOMOS rente conan on ataca npe D Ent 7 1 3 Sensor uoc ctae tae LUN 8 147 Signal FOW mte c um TER 14 2 0 15 21 Co CCo eon co coe cs 15 2 1 1 coo oe ERE ORE UE 15 Sl 2 S12 17 2 2 Mechanical InstallatiOl seed oe puse 18 rome
64. the length in meters Max 15 m 50 ft recommended Optional 2 conductor twisted shielded 20 AWG PVC jacket where is the length in meters Max 15 m 50 ft recommended P N 80002 7 May 2007 Sentry Visibility Sensor User s Guide 1 3 Sensor Description The Sentry is a compact sensor consisting of three 3 major components mounted to a cross arm as shown in Figure 1 3 1 A description of the major components is provided in Table 1 3 1 Table 1 3 1 Component Description and Function TX Head Externally the TX Head consists of a weatherproof enclosure to enclose the electrical and optical assemblies and a hood to protect the optics from direct sunlight and precipitation If the hood heater is ordered the hood will have a silicone heater adhered to the underside to help prevent snow from blocking the optics Housed in the TX enclosure are a Transmitter PCB high power LED optical lens with heater and mounting brackets There are no user serviceable parts in the TX Head WARNING Opening the TX Head will void the warranty of the sensor RX Head Externally the RX Head consists of a weatherproof enclosure to enclose the electrical and optical assemblies and a hood to protect the optics from direct sunlight and precipitation If the hood heater is ordered the hood will have a silicone heater adhered to the underside to help prevent snow from blocking the optics Housed in the RX enclosur
65. tor The RX PCB provides amplification and bandpass filtering of the received signal before being sent to the Signal Processor PCB The power and signal cable from the RX Head terminates at J2 on the Signal Processor PCB in the Main Electronics Enclosure Sample Z RX Head Z Volume TX Head Photodetector A E Modulator PreAmp BP Filter LED Optics Optics EE J J li HTR Power DC bag c p SEP et cite te aay Ee Power TX Sync HTR DC Power Fower Signal 1 4 a EE i N Hood culi des MM Power i 5 DC Power Distribution Output Options m DC Power AC Power Supply 5 EMI Filter AC Surge Protection Output Surge Protection 9 V Main Electronics Enclosure A 2 gt Analog VDC t gt 4 20 Power poe Control Relays Dashed Lines are Options Figure 1 4 1 Sentry Signal Flow Diagram P N 80002 14 May 2007 Sentry Visibility Sensor User s Guide 2 0 Installation 2 1 Site Preparation Site selection and preparation are critical for the successful performance of the Sentry Visibility Sensor If a good location for the sensor is not chosen the sensor is not installed correctly it will not measure data that is representative of the visibility in the area 2 1 1 Siting Guidelines General guideline
66. ull scale output sensors with P N SVS1 x 1 Sensor Cal Voltage EXCO 30 VDC For 5 VDC full scale output sensors with P N SVS1 x 2 Sensor Cal Voltage EXCO 60 VDC Remember that the visibility range of the Sentry is usually 16 km If the range is the optional 10 km it will be marked on the inside of the Main Electronics Enclosure 14 Read the DVM and adjust R17 Span Pot of the Signal Processing PCB to the calculated cal voltage recorded in Step 13 1 mV 15 Remove the Scatter Plate and ND4 Filter return all parts to the Attach Case 16 Disconnect the DVM from the DA System or Signal Processing PCB 17 Close and secure the door of the Main Electronics Enclosure P N 80002 43 May 2007 Sentry Visibility Sensor User s Guide 4 2 Procedure for Calibrating the Sentry with 4 20 ma Current Output Note This procedure may be used with either the standard single ended or the isolated 4 20 ma current output Step Procedure 1 Inspect the Scatter Plate and ND4 Filter to insure they are clean free of scratches mechanically sound and have matching serial numbers If you are uncertain about the integrity of the Calibration Fixture contact EnviroTech Sensors for information about returning it for service Clean the sensor windows with common window cleaner and remove any insect nests spider webs or other debris under the hoods to ensure that the optical path is cle
67. unding the Sentry 2 4 2 DC Power Connections Optional 1 Aregulated DC power supply with a rating of 1 A minimum is recommended to power the Sentry A properly sized battery backed solar powered system may also be used 2 Loosen the cord grip on the lower right bottom of the Main Electronics Enclosure 3 Feed a 2 or 3 conductor power cable into the enclosure through the cord grip 18 AWG 0 823 mm or larger wire is recommended 4 Strip 6 mm 1 4 of insulation from each of the conductors and connect them to TB1 of the P N 30006 DC Power PCB Assy as shown per Table 2 4 2 1 and in Figure 2 4 2 1 5 If the ability to remotely control Sentry power is required connect a wire to terminal 3 of TB1 on the DC Power Assy PCB Connect the other end to a TTL line or I O port that can be controlled by the user data acquisition system Remote Control Logic Remote Control Line Sentry Power Status C25 vD TTL High te OFF 6 Tighten the cord grip to secure the power cord P N 80002 26 May 2007 Sentry Visibility Sensor User s Guide 7 Go to Section 2 4 3 for earth grounding the Sentry Table 2 4 2 1 TB1 DC Power Version User Wire Color L1 1036 Po 2 773 RemoePowerShuof Earth Ground GR YL to Ground Stud Optional Hood Heater Components C2 415V e 5
68. upply PCB as shown in Figure 5 4 2 3 and Table 5 4 2 3 below Note When measuring the TP1 input voltage use TB1 2 12 VDC common as the reference For the and TP5output voltages use TP2 of the DC Power Supply PCB as the ground reference Table 5 4 2 3 Test Point Tolerance 1 10 36 VDC 15 0 0 5 4 504 05VDC TP5 5 0 0 25VDC P N 80002 49 May 2007 Sentry Visibility Sensor User s Guide 15V 15 VDC 3 e 5V 5VDC 5 COMMON e er DODE Converter 15V Module 15 VDC e e re EnviroTech Sensors Inc TP1 ASSY 30068 C e v Input Voltage J Figure 5 4 2 3 DC Power Supply Test Points 1 Ifthe TP1 voltage is zero check D1 surge protection D2 reverse protection diode and F1 resettable fuse on the DC Power Supply PCB Replace as needed or return the DC Power Supply for factory repair 2 Ifthe TP1 voltage is lt 10 VDC or gt 36 VDC check for proper DC power from the customer equipment 3 If TP3 or TP5 voltages are out of tolerance replace the DC Power Supply PCB per the remove amp replace instructions in Section 5 4 4 P N 80002 50 May 2007 Sentry Visibility Sensor User s Guide 5 4 8 Troubleshooting Scenarios These scenarios assume that the
69. us 108860014 5 7 WITTE MA 20 A er m zr Z000 N d 1000 N d 858 XH 82d XL 5 J8j amp 8H 5027 sue 1 Schematic AC Version Figure A May 2007 56 P N 80002 Sentry Visibility Sensor User s Guide P N 80002 57 May 2007 Sentry Visibility Sensor User s Guide prus 8nso pu3 0 IQA 95 01 20 9000 N d 5 YIMOd 1002 Aew 02 HONS 9501 Gury INEI Sd 20006 Nid 82d XL sua uJO2 SsJosuesuoejoui ue p ojul OLOL LES OLP 96S8 LES OLV GW eiqunjon AUIAISIA wARUOS 6000 Nid JOMOd DC wine NE Bw unies NO 20A oe 90002 Nid 82d Kejeu e e 40006 E god 08892024 DNAS XL n mes e woo ae WOD SIS HA 1000 82d XH sua Figure A 2 Sentry Schematic DC Version May 2007 58 P N 80002 Sentry Visibility Sensor User s Guide 9002 L HS
70. ween two trained observers they will not agree in their assessment of the visibility Our ability to see a long distance is altered by what are known as obstructions to vision These obstructions fall into two classes hydrometeors that are wet and lithometeors that are dry Examples of hydrometeors include rain snow fog mist drizzle and spray Examples of lithometeors include salt pollen smoke and dust As light propagates through the atmosphere it is attenuated by absorption and scattering from these obstructions to vision The Beer Lambert Boguers law gives the relationship between light attenuation and scattering and absorption The fraction of light lost to scattering and absorption per unit distance in a participating medium is known as the extinction coefficient c The standard unit of measure of extinction coefficient is km Conversion from extinction coefficient to visibility involves different algorithms one for daytime and one for night Daytime visibility is related to the viewing of dark objects against a light sky as previously mentioned For measurement of visibility in the daytime Koschmieder s Law is used V 3 0 Where V is the visibility and o is the extinction coefficient Nighttime visibility is related to the distance at which a point source of light of known intensity can be seen For measurement of visibility at night Allard s Law is used V e Y 0 00336 Where V is the visibility and o is the extinction

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