ANSI/ASAE EP455JUL91
Approved JUL1991by American National Standards Institute Environmental Considerations in Development of Mobile Agricultural Electrical/Electronic Components
Developed by the ASAE Agricultural Equipment Automation Committee; approved by the Power and Machinery Division Standards Committee; adopted by ASAE December1990;revised editorially March1991,July 1991;approved as an American National Standard July1991;reaffirmed by ASAE December1995;reaffirmed for one year December1997.
1Purpose
1.1This Engineering Practice provides an environmental guideline to aid in the design of electrical/electronic components used on mobile agricultural equipment(components implies both discrete devices and assemblies).It also establishes methods for testing and evaluation of these components.
2Scope
2.1This Engineering Practice limits the environmental considerations to the natural climatic conditions
and the equipment-induced conditions to which the components may be exposed.
2.1.1This Engineering Practice is applicable to components on agriculturalfield equipment as defined in ASAE Standard S390, Classifications and Definitions of Agricultural Equipment.
2.1.2The severity of the environment is influenced by the location of the components and the application for which those components are intended.Accordingly,this document specifies several applicable levels of severity and includes suggested application guidelines.
2.2This Engineering Practice includes sections which may not be applicable to all components in the electrical system,and,accordingly, any such concerns must be addressed as exceptions for the specified product.
2.3Test methods recommended in this Engineering Practice are based on measured or calculated conditions.These methods are used to simulate environmental extremes to which the components are exposed. They are suggested only as guidelines and should not be construed to be guaranteed worst case exposure levels.
3Application
3.1Test cycle duration.The recommended methods describe cycles for each type of test.The number of cycles over which the equipment should be tested must be specified.The number of cycles will vary depending upon equipment,location,function and the type of test being conducted(qualification,reliability,etc.).To determine the number of test cycles it is recommended that the product be evaluated in its actual operating environment.While each test cycle is representative of an actual short term environmental cycle,no attempt has been made to equate the cycle with an acceleration factor for reliability or durability projections.These considerations are beyond the scope of this guideline.
3.2Itemization of environmental factors.A complete description of environmental factors is detailed in Section5—Description of Environmental Factors and Test Methods.Environmental factors are listed in Table1with corresponding references.
3.3Concern for combined environmental factors.The agricultural environment consists of many natural and induced factors which may be present simultaneously.In some cases,the effect of a combination of these factors is much more serious than the effect of exposing samples to each environmental factor in series.For example,the suggested test method for humidity includes both high and low temperature exposure.This combined environmental test is very important to components whose proper operation i
editoriallys dependent on seal integrity.Temperature and vibration is a second combined environmental test that can be significant to some components.During design analysis,a careful study should be made to determine the possibility of design susceptibility to a combination of environmental factors that could occur at the planned mounting location.If the possibility of this type of susceptibility exists,a combined environmental test should be considered.
3.4Effects of test sequence.It is recommended that temperature cycle testing be performedfirst in order to condition the sample mechanically, and that electromagnetic interference,EMI,testing be performed last since component susceptibility can be affected by prior exposure to other conditions.All other applicable tests should be done progressively in increasing order of severity.(Reference:Society of Automotive Engineers Standard J1211JUN78,Recommended Environmental Practices for Electronic Equipment Design)
3.5General guidelines
3.5.1Test conditions.Unless otherwise specified,each test shall be conducted under the following conditions:
Ambient temperature:25°CϮ10°C
Supply voltage:14.0V DCϮ0.5VDC
3.5.2Unique items.The following items are unique for given products and/or applications and must be defined for the specific product:
3.5.2.1Impaired function.In general,impaired function implies either impaired performance of the component or component physical degradation.
3.5.2.2Detrimental corrosion.
3.5.2.3Applicable level of test,exception to test,or modification of test.
3.5.2.4Chemical types used in chemical tests.
3.5.2.5Cause for rejection.
3.5.2.6Specific order of test sequence.
3.5.3Accuracy.Test conditions accuracy shall be within the following limits:
Temperature:Ϯ2°C
DC voltage:Ϯ1%
AC voltage:Ϯ2%
Field strength:Ϯ5%
Frequency:Ϯ1%
Time—0to50h:Ϯ1h
Time—over50h:Ϯ5h
Relative humidity:Ϯ5%
Pressure:Ϯ5%
Distance:Ϯ1%
4Deviations
4.1Conflicting requirements.In the event that a conflict exists between this Engineering Practice and a l
egal requirement,the legal requirement shall take precedence and test results shall accordingly note the legal requirement was used.
5Description of environmental factors and test methods
5.1Temperature
5.1.1Operating temperature.Monitor the component,for impaired function,under the conditions indicated in Fig.1with maximum load conditions applied.
5.1.1.1Level of severity
Level1.T͑max͒ϭϩ125°C
T͑min͒ϭϪ40°C
Level2.T͑max͒ϭϩ85°C
T͑min͒ϭ−40°C
Level3.T͑max͒ϭϩ70°C
T͑min͒ϭϪ30°C
5.1.1.2Application guidelines
Engine compartments:Level1
Pressurized cabs:Level2
Windowless operator stations:Level3
Seasonal applications—Deserve special design considerations 5.1.2Storage temperature.With the component not operating,subject it to an ambient temperature transition from25°C to T(min)at an average rate of less than0.5°C/min and from T(min)to T(max)at the
Table1–Itemization of environmental factors
Environmental factors Paragraph Reference Environmental factors Paragraph Reference Temperature 5.1Electrical transient
Operating temperature 5.1.1SAE J1211,Section4.1,conditions 5.11SAE J1211,Section4.11
Fig.2A Accessory noise 5.11.1
Storage temperature 5.1.2SAE J1211,Section4.1.1.5Alternatorfield decay 5.11.2
Thermal shock 5.1.3SAE J1211,Section4.1.1.5.3Batteryless operation 5.11.3
Inductive load switching 5.11.4
Altitude 5.2SAE J1211,Section4.6Load dump 5.11.5SAE J1113
Operating 5.2.1Mutual coupling 5.11.6
Storage 5.2.2
Electrostatic discharge 5.12DOD HDBK263
Dust 5.3SAE J1211,Section4.5IEC Publication348
SAE J726Surface 5.12.1
Connectors 5.12.2
Solar radiation 5.4
Ultraviolet effects 5.4.1MIL STD810C,Humidity 5.13SAE J1211,Section4.2,
Method505.1,Procedure I Fig.3A
Readability 5.4.2Exposure 5.13.1
Soak 5.13.2MIL STD202F,Method103B Immersion 5.5SAE J1211,Section4.4
Mechanical shock 5.14SAE J1211,Section4.8 Wash 5.6SAE J1211,Section4.4Operational 5.14.1MIL STD202F,Method
213B,Test Condition J Particle impact 5.7SAE J1211,Section4.5Handling 5.14.2
SAE J400Shipping 5.14.3
Chemicals 5.8SAE J1211,Section4.4Mechanical vibration 5.15
Spray exposure 5.8.1Random 5.15.1MIL STD202F,Method Brush exposure 5.8.2214-1,Test Condition A
Sinusoidal 5.15.2MIL STD202F,Method
Salt exposure 5.9MIL STD202F,Method101D201A,204D
ANSI/ASTM B117-73Resonance search 5.15.3SAE J1211,Section4.7 Electrical steady
state conditions 5.10SAE J1211,Section4.10Electromagnetic
Operating voltage 5.10.1compatibility 5.16SAE J1113
Over-voltage 5.10.2Susceptibility
Reverse polarity 5.10.3(component level) 5.16.1
Short circuit protection 5.10.4Open-field 5.16.2
Memory retention 5.10.5Emissions 5.16.3FCC Docket20780, Starting voltage 5.10.6Part15,Subpart J Power-up operational SAE J551
requirements 5.10.750/60Hz‘‘E’’
field susceptibility 5.16.4NBSIR77-1311
Combined environments 5.17
same rate.Allow the component to soak at each temperature extreme for at least4h.Return to ambient(25°C),at an average rate of less than 0.5°C/min.Upon completion,test for impaired function.
5.1.2.1Levels of severity
Level1.T͑max͒ϭϩ125°C
T͑min͒ϭϪ55°C
Level2.T͑max͒ϭϩ85°C
T͑min͒ϭϪ40°C
5.1.3Thermal shock.With the component not operating,subject it to an ambient thermal shock transition from25°C toϪ40°C at the minimum rate of4°C/min and fromϪ40°C toϩ70°C at the same rate.Hold the component at each temperature extreme for1h.Return to ambient (25°C)at the minimum rate of4°C/min.Upon completion,test for impaired function.
5.2Altitude
5.2.1Operating.Monitor the component at the operating extremes,for impaired function after exposure to those specified extremes for1h. Range:Sea level to an elevation of3658m.(Atmospheric pressure of 101.3kPa to62.1kPa)
5.2.2Storage(,shipping).Monitor the component for impaired function after exposure to the extremes specified for1h. Range:Sea level to an elevation of12192m.(Atmospheric pressure of 101.3kPa to18.6kPa)
NOTE:–The low pressure condition is often accompanied by low temperature conditions.
5.3Dust(inorganic).Test the component in a dust chamber containing the equivalent of air cleanerfine dust(particle size as defined by SAE Standard J726MAY81,Air Cleaner Test Code).Sufficient air movement must be provided to maintain a minimum suspended concentration of 0.88g/m3with the component positioned in its normal mounting orientation.Run the test for a minimum of24h.Upon completion,test for impaired function at elevated humidity(see paragraph5.13)and inspect for dust leaks.
5.3.1Levels of severity
Level1.Dust inside the component and/or impaired function caused by the presence of dust.
Level2.Impaired function caused by the presence of dust.
5.3.2Application guideline.Determine the level of severity,dependent upon the component location and function.
5.4Solar radiation
5.4.1Ultraviolet effects.Expose the component to43to75W/m2of ultraviolet radiation(280to400nm wavelength)at a distance of0.75m from the light source for300h.Inspect for degradation beyond a previously specified limit or impaired function after exposure.5.4.1.1Application guideline.Consideration should be given to the filtering effects of windshield glass on the specified UV frequency spectrum.
5.4.2Readability.Observe information displayed on component for legibility at both the maximum and minimum operating ambient light levels.Test for impaired readability beyond a predefined acceptance level.
Level1.Maxϭ1080001x͑exposed location/sunny day)
Minϭ01x
Level2.Maxϭ360001x͑shaded location)
Minϭ01x
5.4.2.2Application guidelines
Non-cab installations:Level1
Cab installations:Level1or2
5.5Immersion.Allow the component(with applicable cables connected) to reach a stable operating temperature,then immerse it in tap water at a temperature of18°CϮ5°C to a component top surface depth of460 mm.Orient the component in each of3orthogonal planes for5min in each plane.Upon removal,immediately subject the component to a cold soak ofϪ10°C in its normal mounting orientation for30min.Return the component to a dry air(40%R.H.)atmosphere of25°C for60min.Test for impaired function.
Level1.Test for impaired function during,as well as after,immersion and conditioning.
Level2.Test for impaired function after immersion and conditioning. 5.5.1Applications guideline.All components which may experience submersion during normal service life.
5.6Wash.Expose the component,in its normal mounting orientation,to the appropriate wash conditions specified.Check for impaired function after exposure.
Level1.7000kPa(pump pressure)and15.9L/min high pressure wash with spray nozzle held a distance of0.1m from the component surfaces for a total of2min.Use a detergent degreaser and a water temperature of60°C.Examine for presence of entrapped water which could potentially impair operation.
Level2.375kPa(pump pressure)and8.3L/min spray wash held a distance of0.1m from component for10min.Use a water temperature of15°C.
5.6.1Application guidelines
Outside cab-mounting locations:Level1
Inside cab-mounting locations:Level2
5.7Particle impact.With the component mounted in its normal configuration expose to470cm3of1.28cm diameter gravel as specified in SAE Standard J400JUN90,Test for Chip Resistance of Surface Coatings,delivered from a35cm distance,at a muzzle pressure of500 kPa.This exposure shall occur12times.Test for impaired function after final exposure.
5.7.1Application guideline.All components located in lower exterior of equipment,or other areas which may be exposed to impact.
5.8Chemicals.Use either spray or brush,whichever is appropriate for the product application.If more than one chemical is specified,each chemical should be applied to a different component under test.
5.8.1Spray exposure.The component shall be mounted in its normal orientation.Subject the normally exposed surfaces of the component to the specified chemical sprayed at low pressure not exceeding375kPa, at an angle ofϮ45deg to the surface of the component,for2min each day for a total of5days.Check for impaired function or detrimental corrosion during the test and at the end of a100h minimal interval followingfinal exposure to test conditions.
5.8.2Brush exposure.Apply the specified chemical solution with a brush until evenly coated over the normally exposed surface
area. Figure1–ambient temperature,24h cycle
Repeat once per day for3days.Check for impaired function or detrimental corrosion during the test and at the end of a100h minimal interval followingfinal exposure to test conditions.
5.9Salt exposure.With the component mounted in its normal orientation expose it for48h to an atomize
d fog made from a5% aqueous solution of NaCl with a temperature of35°C and pH between
6.5and
7.2.
Level1.Check for evidence of salt inside the component,impaired function,or excessive corrosion immediately after the test and at the end of a100h minimal interval following the test.
Level2.Check for impaired function immediately after the test and at the end of a100h minimal interval following the test.
5.10Electrical steady-state conditions
5.10.1Operating voltage.Test component for impaired function while operating over the specified voltage range.
Level1.9VDC to16VDC
Level2.10.5VDC to16VDC
5.10.2Over-voltage
Level1.Test component for impaired function during5min operation at 26VDC.
Level2.Test component after operating at26VDC for5min.
5.10.3Reverse polarity.Test component for impaired function, following the application ofϪ26VDC to its power source for a5min duration.
5.10.4Short-circuit protection.Test component for impaired function after shorting each external lead to system ground and to16VDC for5 min with appropriate protection systems in place.
5.10.5Memory retention
Level1.The permanent data memory of the component shall withstand total loss of power for1year with no memory loss.
Level2.The permanent data memory of the component shall withstand reduction of power to5VDC for5s at its power source with no memory loss.
5.10.6Starting voltage.Test component for impaired function when its power source voltage is5.3VDC,having just previously ramped up from 0VDC.
5.10.7Power-up operational requirements.Test component for impaired function as its power source voltage is ramped from0to minimum operating level at the maximum rate of1V/ms.
5.11Electrical transient conditions
5.11.1Accessory noise.Test component for impaired function when a voltage of14+1.5sin(2f•t)is applied to its power source.Time is denoted by t.Frequency,f,is to be swept logarithmically from50Hz to 10kHz over a5min period.Source impedance is1ohm.
5.11.2Alternatorfield decay.Test component for impaired function after power line exposure to a transient of−90eϪt/0.038V having a source impedance of15ohms.This test shall be repeated at a rate of0.2 Hz for60test cycles.The test shall be initiated as+14VDC power is disconnected.
5.11.2.1Application guideline.The level of severity must be determined and is dependent upon the component location and function.
5.11.3Batteryless operation.Apply a voltage of6+͉12.6sin(2f•t)͉to the power source for the component.
Frequency,f,is to be swept from 500Hz to1.5kHz over a5min period.The source impedance should be 2.5ohms.
Level1.Test component throughout exposure for impaired function. Level2.Test component for impaired function following exposure.
5.11.3.1Application guideline.The level of severity must be determined and is dependent upon the component location and function. The appropriateness or validity of this condition,being somewhat application dependent,should also be determined.5.11.4Inductive load switching.Apply14Ϫ300eϪt/0.001V with a source impedance of20ohms to the power source of the component at a1.0Hz rate for300test cycles.
Level1.Test component for impaired function during exposure. Level2.Test component for impaired function following exposure.
5.11.4.1Application guideline.Determine the level of severity, dependent upon the component location and function.Determine the frequency and duration(number of cycles)of this test based on the specific application.
5.11.5Load dump.Apply14ϩ106eϪt/0.188V to the power source of the component with a source impedance of2.5ohms and1.54mH at a0.01 Hz for5test cycles.
Level1.Check for impaired function during test.
Level2.Check for impaired function after test.
5.11.5.1Application guideline.Establish the severity of the particular application based on specific alternator characteristics and component locations.Values should,therefore,be altered accordingly.
5.11.6Mutual coupling
5.11.
6.1Power source lines
Level1.Superimpose[450eϪt/(14ϫ10Ϫ6)]sin(2ϫ106t)V to the power source for the component at a10Hz rate for10cycles.The source impedance should be50ohms.Check for impaired function during test. Level 2.Apply14+200e-t/(14ϫ10Ϫ6)V to the power source for the component at a1.0Hz rate for300test cycles.The source impedance should be50ohms.Check for impaired function after test.
5.11.
6.2Signal/input/output lines.ApplyϮ200eϪt/(14ϫ10Ϫ6)V to non-power source lines at a 1.0Hz rate for300test cycles.Source impedance should be50ohms.Check for impaired function following test.
5.11.
6.3Application guideline.Determine the level of severity, dependent upon the component location and function.
5.12Electrostatic discharge
5.12.1Surface.Subject the component surface in its normal mounting configuration to aϮ25kV electrostatic discharge for a total of10pulses, 5of each polarity.The test probe shall have a diameter of14mm and a length of80mm and shall conform to International Electrotechnical Commission Publication348,Safety Requirements for Electronic Measuring Apparatus(Electrostatic Discharge).The test probe shall approach the component at a rate of0.1m/s until a discharge occurs. Test points shall be specified.The test set-up shall be as shown in Fig. 2.
Level1.Check for impaired function during test.
Level2.Substitute a peak voltage ofϮ15kV in the test described in paragraph5.12.1.Check for impaired function after test.
5.12.1.1Application guideline.Determine the level of severity, dependent upon the component location and function.
5.12.2Connectors.Subject the connector of the component,while it is disconnected from its wiring harness,to aϮ25kV electrostatic discharge for a total of10pulses,5of each polarity.The test probe shall have a diameter of14mm and a length of80mm and shall conform to IEC Publication348,Safety Requirements for Electronic Measuring Apparatus(Electrostatic Discharge).The test probe shall approach the connector at a rate of0.1m/s until the discharge occurs.Test points shall be specified.The test set-up shall be as shown in Fig.2.
Level1.Check for impaired function after test.
Level2.Substitute a peak voltage ofϮ15kV for the voltage specified in the test described in paragraph5.12.2.Check for impaired function after test.
5.12.2.1Application guideline.Determine the level of severity, dependent upon the component location and function.
5.13Humidity
5.13.1Exposure
Level 1.Subject component to the cycle in Fig.3for a minimum of 48h.Check for impaired function during this cycle with vapor pressure controlled to prevent condensation.
5.13.2Soak.Soak the operating component in 96%relative humidity at 38°C for a minimum of 240h.Check for impaired function following the soak.
5.14Mechanical shock.Check for impaired function,loose parts,or visible cracks upon completion of the following tests.
5.14.1Operational.The component shall withstand a single 11ms half-sine pulse of 490m/s 2in 3mutually perpendicular axes using the component’s normal mounting configuration as one reference plane.5.14.2Handling
5.14.2.1Installation.Support component and the far end of the harness at the same elevation,then release the component,allowing it to free-fall without striking any objects,while still holding the far end of the harness.This procedure shall be repeated 10times.Evaluate component for excessive stress to o
r failure of connectors,terminals,crimp points,strain relief,etc.(Reference:SAE Standard J1211JUN78,Recommended Environmental Practices for Electronic Equipment Design)5.14.2.2Bench
Level 1.Drop the component a distance of 400mm onto a hardwood bench top at least 40mm thick,repeat on all practical edges and faces.Level 2.Place the component on a hardwood bench top at least 40mm thick.Using one edge as a pivot,lift the opposite edge of the component 45deg and drop.Repeat this test,dropping the component once on all practical edges and faces.
5.14.3Shipping.The component in its shipping container shall be dropped 1200mm onto a 50mm thick plywood surface backed by concrete or a rigid steel frame.
5.15Mechanical vibration.Because vibration parameters are highly application dependent,application data should be used to determine the operating and test specification.In lieu of this data,levels currently used in ag-industry applications are provided.A combination of resonant search test and one of the other methods detailed herein is recommended.Monitor the functional performance of the component under the specified vibration.The vibration level should be measured and controlled at fixturing,near the component.Check for impaired function during test and loose parts or fatigue cracks upon completion of test.5.15.1Random.Mount the component in its normal mounting configuration.Vibr
ate for a minimum of 2h in each of 3orthogonal axes at 52.4m/s 2RMS overall acceleration and power spectral density of 2m 2/s 3from 50Hz to 2000Hz.Spectral density curve shall conform to profile illustrated in Fig.4.5.15.2Sinusoidal
Level 1.A logarithmic sweep from 10Hz to 2000Hz to 10Hz over a period of 20min shall be performed for a minimum of 4h in each of 3orthogonal axes.The amplitude shall be a constant displacement of 1.5mm peak to peak from 10Hz to 40Hz and at a constant acceleration of 35m/s 2RMS from 40Hz to 2000Hz.
Level 2.Controlled displacement shall be 0.54mm RMS with a logarithmic sweep from 10Hz to 55Hz to 10Hz at a rate of 2min/sweep for a minimum of 2h in each of 3mutually perpendicular axes.
5.15.3Resonance search.Component is to be mounted in each of 3mutually perpendicular axes.A low mass resonance detecting accelerometer shall be mounted on component in the same plane as the vibration exciter travel.A control accelerometer shall be mounted on the vibration fixturing near the component and in the same plane as the vibration exciter travel.
Sweep range:10Hz to 2000Hz at the rate of 1octave/min Acceleration:39m/s 2throughout sweep
Amplification factor constituting a resonance point:Q у5Dwell time at resonance points:5min 5.16Electromagnetic compatibility,EMC
5.1
6.1Susceptibility (component level).Components shall be positioned and connected as close as possible to their product application.The component shall be tested at no less than 6frequencies per octave.If the component is found to have a resonant frequency (i.e.,a point where susceptibility increases sharply),a test shall also be performed about that frequency.The applicable ranges are 14kHz to 1GHz for vertical polarization and 30MHz to 1GHz for horizontal polarization.Check for impaired function during these tests.
Modulation type:
Continuous Wave,CW-14kHz to 1GHz CW
Level 1.Use a field strength of 100V/m in the frequency range from 14kHz to 1GHz.
Level 2.Use a field strength of 20V/m in the frequency range from 14kHz to 1GHz,except 50V/m in the following ranges:
Frequency range MHz
24to 51148to 175445to 517798
to
875
5.1
6.1.1Application guideline
EMC Level 1conformance should normally provide electromagnetic interruption-free performance for electronic systems used in agricultural applications worldwide.
EMC Level 2conformance may possibly result in infrequent
interruption
Figure 2–Electrostatic discharge test
set-up
Figure 3–Humidity test,24h cycle
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