eCO SeNSOrS, INC. vOC GAS SeNSOr Model C‑21
Contents
1. tech notes and other useful information visit our extensive website at www ecosensors com E mail us at sales ecosensors com Eco Sensors Model C 21 RESPONSE RANGES FOR SOME COMMON VOCs DISPLAY CALIBRATION FOR PERC Partial calibration for perchloroethylene First detects Alarm TLV the common dry cleaning fluid First red bar LED Display Concentration ppm ppm ppm ppm Acetone 4 5 20 25 750 Benzene 5 10 25 50 10 All green 20 Diacetone alcohol 5 10 25 50 50 All yellow 40 Formaldehyde 1 5 15 25 0 1 One red 50 Methylene chloride 8 10 40 50 50 Two red 100 Methyl ethyl ketone 3 5 15 20 200 All red 140 Perchloroethylene 5 50 50 Toluene 3 5 15 25 50 Trichloroethylene 10 20 50 100 50 Threshold Limit Value Average estimate of government industrial hygienists for repeated worker exposure C 21 OUTPUT CIRCUITS PLUG OUTPUT WIRING COLOR CODING EARLY VERSION RED GREEN BLACK CURRENT VERSION WHITE RED BRAID 0 2 VOLTS TO DIGITAL VOLT METER RAP 7800 REMOTE CONTROL PANEL OR DATA LOGGER WHITE OR RED a Beech DC OUTPUT SIGNAL R BRAID RELAY CONTACTS BLACK COMMON GROUND POWER RELAY ACCESSORY PLUG 3 5 MM 2 CIRCUIT SUCH AS FAN OR TO SWITCHED LOAD OZONE GENERATOR RELAY POWER SUPPLY 12 24 VOLTS AC OR DC SUGGESTED POWER SWITCHING RELAY CIRCUIT CUSTOMER SUPPLIED The C 21 internal relay is a dry contact FET device It will handle up to 30 volts AC or DC at up to 130 ma so it will swi2. ECO SENSORS INC VOC GAS SENSOR Model C 21 INSTRUCTIONS FOR USE GENERAL The model C 21 is a solid state gas monitor capable of sensing a variety of gases and vapors The ones it is generally sensitive to are called VOCS volatile organic compounds and the most common application of the C 21 is for solvent vapors Common examples are paint thinners dry cleaning fluids cleaning solvents and gasoline vapors The instrument does not respond to carbon dioxide or radon and has only a weak response to carbon monoxide The C 21 is self contained except for its AC adapter power module The instrument also has an audio alarm and has outputs to external alarms data loggers calibration equipment etc OPERATION Plug the AC adapter into AC power and plug the adapter s output plug into the power jack on the instrument After a few seconds most or all of the display will light up it will stay high for 1 2 minutes and then it will go down to as low as one green bar The C 21 will require at least 3 minutes to warm up and 5 or more minutes is recommended The alarm will go on while the instrument s display is in the red including during warm up If this is too objectionable you may put a muffling cloth such as a towel over the instrument during warm up or you may switch the alarm off through a hole in the back cover see illustration to the top right One green bar lit indicates the instrument is receiving correct power Illumination t
3. PUTS TO EXTERNAL EQUIPMENT The C 21 has two output circuits for external measurements and controls via the accessory plug They are refer to drawing on the reverse side of this instruction sheet Low powered transistor relay that will switch up to 30 volts at 130 mA directly or it can drive an external power handling relay that has Its own coil power supply This relay closes when the buzzer actuates because it is programmed by the same DIP switch that controls the buzzer 0 2 volts DC output that increases as the VOC level increases The first red bar on the LED bargraph corresponds to an output of one volt The output is not linear however It Is logarithmic See output table reverse side of this sheet This DC output ran be used to drive data loggers such as the Eco Sensors model DL 2 for PCs a digital voltmeter for remote readout or the Eco Sensors RAP 7800 Remote Access Panel The RAP Panel has a 90 db alarm a pulsating red strobe alarm light and a 4 20 mA output loop to connect to a building control system BCS For RAP systems be sure to order the C21 with an interface terminal block USE IN VEHICLES The C 21 may also be used in cars and trucks or wherever there is 12 volts DC available Acigarette lighter adapter should be purchased for this purpose from an electronics store Make sure the plug selected fits our jack 2 5 mm and that it is configured for center pin Radio Shack has several models that work such as their
4. e side of this instruction sheet BATTERY OPERATION To investigate a VOC leak or to do field research the instrument may be unplugged from the AC adapter and operated from its internal rechargeable battery for about 2 hours This will not work on initial operation The battery will require about 10 hours of charging which happens automatically whenever the instrument is being powered by the AC adapter ALARM The audible alarm buzzer is normally triggered when the first red segment of the LED is lit During warm up of the instrument the sensor will read high for 1 2 minutes and the alarm will actuate unless it has been turned off The alarm set point which is the same set point as for the internal relay contacts can be changed through resetting the 8 toggle DIP switch found on the circuit board This switch allows reconnecting the set point across any of the top 8 bars of the LED display Switch number 1 connects to the top red bar all the way down to switch 8 controlling through the third green bar from the bottom of the display Please note that no more than one switch should be down on at a time If no switch is on the alarm and internal relay will not work Normally the third switch corresponding to the first red bar is on This switch can be shut off using a pen or screwdriver actuating it through the upper middle hole in the back plate When this is done neither the alarm nor the internal relay contacts will function OUT
5. n has a somewhat longer discharge life but the lower voltage version will charge more efficiently If the AC adapter is only putting out 12 13 volts most 12 volt AC adapters like our model P 20 put out about 15 volts under load Do NOT attempt to use alkaline or other non chargeable batteries The non rechargeable batteries will overheat and destroy the instrument voiding the warranty The battery may be replaced by disconnecting the AC adapter and removing the back of the instrument Exchange the batteries being careful to put the now battery in exactly where the old one was and to replace the protective felt material surrounding it Sensor If the instrument no longer responds to gases and vapors the likely cause is sensor failure The replacement sensor is the Eco Sensors part number SE 4 AC Adapter For use in North America and other areas with the American System of 120 V 60 HZ the Eco Sensors P 20 adapter should be used For other areas adapters should be purchased locally that fit local wall sockets and conform to local codes The output should be 12 volts DC unregulated 300 500 mA The plug to our instrument should fit a 5 5 2 5 mm socket with the center pin For further details see our Tech Note P 101 SPECIFICATIONS Sensor Heated metal oxide semiconductor Sensitivity First responds at a few ppm for many VOC gases and vapors Alarm typically sounds at about 50 ppm Response time Within one minute of when gas reache
6. o the first yellow bar indicates a cautionary situation for most VOCs and reaching the first red bar often indicates a hazardous condition such as reaching the OSHA TLV Test the instruments response by holding a fresh felt marker pen a few millimeters from the sensor grill for a few seconds The display should light up to red Check the C 21 s response to gases and solvents of interest by exposing the instrument to these VOC s and noting its response The C 21 s response to common VOC s is shown on the reverse side of this instruction sheet It is best for your protection and for the instrument itself to leave it on 24 hours a day INSTALLATION The instrument may be hung on hooks screws etc using the outer two top holes on the back or it may be stuck to machinery cabinets etc using its magnetic backing Avoid areas that have a lot of vibration dust or dripping or sprayed water The instrument is not designed for outdoor use For dusty or wet areas the C 21 should be mounted in the Eco Sensors EE 1 Environmental Enclosure which protects it from these hazards CALIBRATION The instrument indicates red at high levels of VOC gases and vapors The C 21 is broadly sensitive to most VOCs but its response is different for each one To calibrate for a specific gas a chemical laboratory is required The procedure detailed in our Tech Note C 100 The perchloroethylene calibration perc or dry cleaning fluid is shown on the revers
7. part number 270 029 For vehicular use the instruments panel switch should be in the AC position Vehicular use includes charging the battery In the C 21 checking for leaks in solvent containers inspection of gasoline station and vehicle maintenance areas and environmental checking of roadside hazards and spills OVE R HOLES FOR HANGING a SENSOR REMOVE SCREWS AND COVER TO ACCESS BATTERY CE NOTES CASE WILL BE WARM TO THE TOUCH DURING OPERATION THIS IS NORMAL AND NOT A CAUSE FOR CONCERN THE FUSE IS THE AUTOMATICALLY RESETTING TYPE AFTER A FEW MINUTES COOL DOWN THERE IS NO REPLACEABLE FUSE GAS LEVEL DISPLAY MODEL C 21 VOC SENSOR Alarm Switch Toggle POWER JACK P 20 POWER ADAPTER On Left OUTPUT 12 VDC Off Right Middle Hole in Back Cover SERVICE AND MAINTENANCE The battery and the sensor are the only user serviceable parts of the instrument While they should last 3 5 years It is good practice to replace them annually Battery The nickel cadmium NiCad battery 9 volt snap on connector generally does not fail suddenly After about a year Its performance will gradually decline The battery replacement is Eco Sensors part number XB C2 NiCad batteries are also available in local electronics stores such as Radio Shack part number 23 526 Both NiCad and NiMH batteries will work and both 7 2 volt 6 cell and 8 4 volt 7 cell models will work The higher voltage versio
8. s the sensor Audio alarm level Approximately 80 db Temperature and humidity range 0 40 deg C and 0 80 relative humidity Supply voltage required 12 volts DC 200 mA Battery life Over 2 hours per charge Size of instrument 85 X 35 X 60 mm 3 1 4 X 1 3 8 X 2 3 8 Weight of instrument 140 grams 5 oz Shipping weight of instrument and adapter about 2 3 kg 1 1 2 Ibs SAFETY FEATURES Enclosure Self extinguishing ABS plastic Sensor Heated element is flame arrestor protected Electrical a Circuits operate at 24 volts 250 mA or less with no high capacity inductors or capacitors b Self resetting fuse to protect against excess input current flow d Overvoltage protection diode barrier to protect against supply voltage surges spikes overvoltage and reverse polarities PRECAUTIONS Allow at least 5 minutes warm up Read all instructions in this manual Keep instrument dry Never let water or other liquids into the sensor Do not drop the instrument or subject It to continuous vibration Do not store in high levels of dust Do riot clean the instrument with cleaning chemicals or solvents Clean it with a damp cloth Do not operate near heavy aerosols spray usage or where oxygen Is being administered Call a qualified electrician If you have any doubts about voltages currents electrical practice etc WARRANTY This product is warranted against defects in materials and workman
9. ship for one year following the date of purchase by the original owner This warranty does riot include damage to the product as a result of misuse accident damage modifications or alterations and it does riot apply if the instructions in this manual are not followed If a defect develops during the warranty period Eco Sensors at its election will repair the instrument or replace it with a new or reconditioned model of equivalent quality In the event of replacement with a new or reconditioned instrument the replacement until will continue the warranty of the original unit To return the instrument contact your distributor or call Eco Sensors at 800 472 6626 or e mail at sales ecosensors com to receive return instructions and a Return Goods Authorization RGA number Except as provided herein Eco Sensors makes no warranties express or Implied Including warranties of merchantability and fitness for a particular purpose Eco Sensors shall not be liable for loss of use of Oft instrument or other incidental or consequential damages expenses or economic low or claims for such damage or economic loss This warranty gives you specific legal rights and you may also have other rights which vary from state to state RECORD YOUR SERIAL NUMBER HERE KEEP THIS MANUAL AND WARRANTY FOR YOUR RECORDS Eco Sensors is a registered trademark of Eco Sensors Inc Eco Sensors Inc 2006 Revision 3 for C 21 REV 1 For brochures application and
10. tch low voltage alarms directly For switching power loads an intermediate relay and power supply should be used such as shown above RECOMMENDED ACCESSORIES EE 1 Environmental Enclosure For dust and water protection in industrial and agricultural environments and where the public may be near the instrument 120 x 180 x 90 mm 5 x 7 x 3 with a clear polycarbonate gasket front cover DL Series Data Loggers Tiny battery operated data loggers record data for later analysis in PCs RAP 2 Remote Alarm Panel In rugged PVC enclosure Feature 90 dB audio alarm red alarm strobe light 4 20 mA analog signal loop for building control systems and optional digital readout
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