WORKING DRAFT UGANDA 
STANDARD  
  US 2277 -2 
First  Edition  
2020 -mm-dd 
 
 
 Reference nu mber  
US 2277 -2: 2020 
© UNBS 2020   
  
Road vehicles  — Maximum road speed limiters  — Part 2: 
Specification for system and component  
 US 2277 -2: 2020  
ii © UNBS 2020  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions  of a contract. Users are 
responsible for its correct application  
© UNBS 2020   
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photo copying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  US 2277 -2:2020  
© UNBS 2020  – All rights reserved  iii 
 Contents  
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Durability and environmental performance  ................................ ................................ ........................  2 
4.1 System durability  ................................ ................................ ................................ ................................ ... 2 
4.2 Time and temperature stability  ................................ ................................ ................................ ............  2 
4.3 Electrical power supply  ................................ ................................ ................................ ........................  2 
4.3.1  Steady state voltage  ................................ ................................ ................................ ..............................  2 
4.3.2  Ripple  ................................ ................................ ................................ ................................ ......................  2 
4.3.3  Reverse polarity  ................................ ................................ ................................ ................................ ..... 2 
4.3.4  Transients.  ................................ ................................ ................................ ................................ .............  3 
4.3.5  Input/output protection  ................................ ................................ ................................ .........................  3 
4.3.6  Electromagnetic compatibility  ................................ ................................ ................................ .............  3 
4.4 Environmental protection  ................................ ................................ ................................ .....................  3 
5 Marking  ................................ ................................ ................................ ................................ .............................  4 
A.1 5 
A.2 Activate the system through the following test cycle:  ................................ ................................ ...... 5 
A.3 Repeat this test cycle for 250 000 cycles.  ................................ ................................ ...........................  5 
D.1 Chassis and cab mounted components  ................................ ................................ ................................ .... 8 
E.1 General  ................................ ................................ ................................ ................................ ........................  98 
E.2 Change of temperature (thermal shock)  ................................ ................................ ................................ .. 98 
E.3 Resistance to dust  ................................ ................................ ................................ ................................ ..... 98 
E.4 Salt mist test  ................................ ................................ ................................ ................................ ...............  98 
E.5 Contamination  ................................ ................................ ................................ ................................ ............  98 
E.6 Driving rain: chassis mounted components  ................................ ................................ ..................  109 
E.7 Mycological  ................................ ................................ ................................ ................................ ...............  109 
 US 2277 -2: 2020  
iv © UNBS 2020  – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a paras tatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO ) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committe es. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by t he Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS/TC 08, transport and 
communication   
WDUS 2277:2020 consists of the following parts, under the general title Road vehicles — Maximum road 
speed limiters for motor vehicles :  
  Part 1: Performance and installation requirements  
  Part 2: Specification for system and component requirements  
 UGANDA STANDARD  US 2277 -2: 2020  
 
© UNBS 2020 – All rights reserved  1 
 Road vehicles  — Maximum road speed limiters  — Specification 
for system and component  
1 Scope   
This Part of Uganda Standard specifies requirements fo r the performance of systems and components 
designed to form part of a speed limiter intended to limit the maximum road speed of motor vehicles by control 
of engine power . 
2 Normative references  
The following referenced documents referred to in the text in  such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
ISO 763 7-1; Road vehicles -- Electrical disturbances from conduction and coupling -- Part 1: Definitions and 
general considerations  
ISO 7637 -2; Road vehicles -- Electrical disturbances from conduction and coupling -- Part 2: Electrical 
transient conduction along supply lines only  
IEC 60068 -2-1, Environmental testing - Part 2 -1: Tests - Test A: Cold Stability  
IEC 60068 -2-2, Environmental testing - Part 2 -2: Tests - Test B: Dry heat Stability.  
IEC 60068 -2-10, Environmental testing - Part 2 -10: Tests - Test J and gu idance: Mould growth Stability.  
IEC 60068 -2-11, Environmental testing - Part 2: Tests. Test Ka: Salt mist Stability  
IEC 60068 -2-14, Environmental testing - Part 2 -14: Tests - Test N: Change of temperature Stability   
IEC 60068 -2-18, Environmental testing - Part 2 -18: Tests - Test R and guidance: Water Stability   
IEC 60068 -2-38, Environmental testing - Part 2 -38: Tests - Test Z/AD: Composite temperature/humidity cyclic 
test Stability  
3 Terms and definitions  
For the purposes of this document, the following ter ms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp   
2 © UNBS 2020  – All rights reserved  
 3.1  
Permanent damage  
Damage sustained by a component or sy stem which renders it inoperative. For the purpose of this definition 
the rupture of a fuse or the operation of other user serviceable circuit protection devices is not taken to be 
permanent damage  
3.2 
Normal function  
Functioning in accordance with the re quirements of Part 1 of this standard  
3.3 
Failure to function  
Functioning outside the requirements of Part 1 of this standard but not suffering any permanent damage  
3.4  
Nominal voltage  
A voltage of 12± 1 V d.c or 24±2 V d.c.  
4 Durability and environment al performance  
4.1 System durability  
The system, in a condition equivalent to new, shall be tested in accordance with Appendix A and, after 
completion of the test, shall comply with the manufacturer’s specification . 
4.2 Time and temperature stability  
The system, in a condition equivalent to new, shall be tested in accordance with Appendix B. During the 
procedures in B.1 to B.7 and B.9 the sensed speed shall not differ from the set speed by more than 3.2 km/h.  
4.3 Electrical power supply  
4.3.1  Steady stat e voltage  
4.3.1.1  The system shall function normally when connected to a power supply in the range (12/24V) d.c. 
4.3.1.2  The system shall be tested at (5 V and 28 V) d.c., for a period of 10 min at each, with a sweep 
between these maximum and minimum valu es. The change from nominal voltage to each extreme and from 
each extreme to nominal voltage shall take place over a time interval of 10 ms. The system may fail to 
function but it shall not be permanently damaged and shall return to normal function when th e power supply is 
returned to normal.  
4.3.2  Ripple  
Normal operation of the system shall not be affected by regular or irregular variations in voltage about the 
prevailing supply level (excluding transients) not exceeding 3V (± 2 Vdc) peak to peak in the r ange 10 Hz to 
10 kHz.  
 4.3.3  Reverse polarity  
The system may fail to function but it shall not be permanently damaged when subjected to a reversal of 
polarity of the supply referred to in 3.3.1.1 for 1 min and shall return to normal function when the power  supply 
is returned to normal.  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  3 
 4.3.4  Transients.  
Tests for immunity to transients shall be conducted in accordance with ISO 7637 -1 for 12 V systems and ISO 
7637 -2 for 24 V systems. Transient voltage test severity levels are given in Appendix C  
4.3.5  Input/ output protection  
 4.3.5.1  Each output in turn shall withstand connection to earth for 1 min duration, without permanent 
damage, with the system operating and shall return to normal function when the connection is removed.  
 4.3.5.2  Each input in turn shall  withstand a connection to earth and to supply for 1 min, without 
permanent damage, with the system operating and shall return to normal function when the connection is 
removed.  
4.3.6  Electromagnetic compatibility  
4.3.6.1  Supply line interference.  
When tes ted in accordance with BS 3G 100 -4.2:1980 (civil applications), the system shall operate correctly 
with 3 V r.m.s. interference, at any frequency in the range 1 MHz to 150 MHz, superimposed on either battery 
supply line with respect to a reference ground p lane.  
4.3.6.2  Electromagnetic emissions.  
Using the test procedure described in paragraph 4 of DIN 57879 3:1981 and with the values of 
electromagnetic emissions measured on the output port of a 50 Ohm line impedance stabilizing network using 
a CISPR quasi -peak measuring receiver (both of which shall meet the requirements of BS 727), the system 
under test shall not cause interference in the supply line exceeding the values shown in Table 1, or their 
equivalent if other equipment is used  
Table 1 — Maximum supp ly line interference levels  
Type  Frequency band MHz a Measured level relative to 1 microvolt 
in 50 ohm(+ dB)  
0.15 to 0.29  70 level  
0.30 to 4.90  60 level  
5.00 to 29  50 level  
30 to 108  Slope 50 to 30  
4.3.6.3  RF field susceptibility  
When tested in accord ance with the procedure described in DEF STAN 59 41, Part 3, Issue 2:1986 (DRSO2 
radiated susceptibility) the system shall function normally when subjected to an R F field of 140 dB above 1 
µV/m (10 V/m) over a frequency range of 1 MHz to 220 MHz.  
4.4 Envi ronmental protection  
4.4.1  Components of the system shall be subjected to the following tests, after each of which they shall 
continue to function normally.  
4.4.2  Low temperature storage test in accordance with IEC 60068 -2-1 at a temperature of:  
a) 0 °C fo r cab mounted components; b) 0 °C for engine and chassis mounted components. The period for 
this test shall be 96 h after the component has reached the required temperature. Return the component to 18 
± 2 °C at a rate not exceeding 1 °C/min and test.  
4.4.3  Using the component tested under 4.4.2, carry out a high temperature storage test in accordance with 
IEC 60068 -2-2 at temperature of:   
4 © UNBS 2020  – All rights reserved  
 a) + 80 °C for cab mounted components;  
b) + 140 °C for engine mounted components;  
c) + 100 °C for chassis mounted compone nts. 
The period for this test shall be 96 h after the component has reached the required temperature  
 Return the component to 18 ± 2 °C at a rate not exceeding 1 °C/min and test.  
4.4.4  Using the component tested under 4.4.3 Carryout a humidity storage test  in accordance with IEC 
60068 -2-38 and test after the drying period.  
4.4.5  Using the component tested under 4.4.4 carry out a sinusoidal vibration test as given in Appendix D, 
and after, test for normal function.  
NOTE Additional tests which may also be con sidered by manufacturers are described in Appendix E.  
5 Marking  
Each control unit and actuator shall be marked with the following:  
a) The number of this Uganda Standard,  
b) The name and/or trade mark of the manufacturer;  
c) A part number  
d) Serial number  
e) Country of origin  
NOTE  Note integrated in the text.  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  5 
 Annex  A 
(normative)  
 
System durability tes t 
A.1 
Connect the components of a system in accordance with the manufacturer’s instructions and where necessary 
adjust to simulate maximum load/travel condition s (worst case). Connect a 24 V (12 V) battery with the charge 
maintained at 28 (14) ± 1 V d.c  
A.2 Activate the system through the following test cycle:  
a) Drive to a full range travel (t1);  
b) Reverse to zero output (t2);  
c) Drive to a mean position (t3);  
d) Control at mean  output for 5 × (t1 + t2 + t3);  
e) Reverse to zero output; where t is the time required to complete each individual operation  
A.3 Repeat this test cycle for 250 000 cycles.   
6 © UNBS 2020  – All rights reserved  
 Annex  B 
(normative)  
 
Time and temperature stability test  
B.1 Connect up the system in a test chamber at 18 ± 2 °C (see Figure 1) to a supply of 28 (14) ± 1 V d.c. , 
complete with simulation of components of the loop between the throttle actuator and speed (i.e. engine a nd 
transmission) outside of the test chamber.  
B.2 Set simulated throttle demand to maximum.  
B.3 Adjust the set speed of the system where appropriate.  
B.4 Activate the system and the recorder. Throughout the test, B.5 to B.7, record the maximum deviation  from 
the set speed.  
B.5 Allow the system to operate for 10 h.  
B.6 Reduce the test chamber temperature to 0 ± 2 °C. After the temperature of the test chamber has 
stabilized, operate the system for a further 30 min.  
B.7 Increase the test chamber temperat ure to 60 ± 2 °C . After the temperature of the test chamber has 
stabilized, operate the system for a further 30 min.  
B.8 Increase the test chamber temperature to 80 ± 2 °C . After the temperature of the test chamber has 
stabilized, operate the system for  a further 30 min. The system shall continue to function but the accuracy may 
be degraded.  
B.9 Reduce the test chamber temperature to 60 ± 2 °C. After the temperature of the test chamber has 
stabilized, operate the system for a further 30 min. Record the maximum deviation from the set speed.  
 
 Figure 1 – Test Layout  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  7 
 Annex  C 
(normative)  
 
Transient voltage test severity levels  
Normal function A  
Fail but recover C  
Table 2 — Transient voltage test severity l evels  
Test pulse  Test level  Functional 
status  Number of 
pulses or test 
time Remarks  
1 -150 ( -75) C 5000   
2 +150 ( +75) C 5000   
3(a) -150 ( -75) A 1h  
3(b) +150 ( +75) A 1h  
4 -12(-6) C 5 pulses  1 min between 
each other  
5 +180 (+80 ) C 1 pulse   
NOTE Thes e values are for use in conjunction with ISO 7637 -1 or ISO 7637 -2  
8 © UNBS 2020  – All rights reserved  
 Annex  D 
(normative)  
 
Sinusoidal vibration test  
D.1 Chassis and cab mounted components  
D.1.1 General  
Subject the component to be tested, mo unted on its normal mount, complete with its ancillary components, to 
a resonance search in all three planes using a sinusoidal wave form under the conditions given in D.1.2 
followed by an endurance test under the conditions given in D.1.3.  
D.1.2 Resonanc e search  
Frequency range  40 Hz to 2 000 Hz  
Input  6 gn 
Sweep time  2 min  
duration  Long enough to establish resonant frequencies  
D.2.3 Endurance test at resonance ranges  
Frequency range  3 dB below peak for each resonance in the 
ranges 40 Hz to 20 0 Hz and 200 Hz to 2 000 Hz  
Input  12 gn       6 gn  
Sweep time  2 Hz/s            5 Hz/s  
duration  107 reversals at resonant frequency  
If there is no resonance, carry out a broad sweep endurance test under the following conditions  
Frequency range    40 Hz to 200 Hz , 200 Hz to 2 000 Hz  
Input  12 gn  ,     6 gn 
Sweep time  2 Hz/s     ,       5 Hz/s  
duration  10 h/plane              ,                 10 h/plane  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  9 
 Annex  E 
(informative)  
 
Additional tests  
E.1 General  
The te sts given in E.2 to E.6 may be considered by system component manufacturers  
E.2 Change of temperature (thermal shock)  
Mount the component in its normal operating attitude and test in accordance with test Na of  IEC 60068 -2-14 
using the following minimum an d maximum temperatures  
a)  0 °C to + 65 °C for cab mounted components;  
b) –0 °C to + 120 °C for engine mounted components;  
c) –0 °C to + 85 °C for chassis mounted components  
Subject the component to 20 cycles and use an exposure time at each temperature of  2 h. Return the 
component  to 18 ± 2 °C at a rate not exc eeding 1 °C/min and test for normal operation  
E.3 Resistance to dust  
E.3.1 Locate the component in a box 900 mm cube internally, in its normal operating attitude, on a pedestal 
raising it 150 mm abov e the base of the box, and positioned at least 150 mm from any wall of the box.  
Introduce on the floor of the box a mixture of 4.5 kg of fine powdered cement complying with KS 18 -1/2 and 
agitate by projecting blasts of air for 2 s pointed in a downward dir ection in such a way that the mixture is 
uniformly diffused within the box. Repeat the cycle every 15 min over a period of 5 h.  
E.3.2 Conduct the test in accordance with Appendix A for 25 000 cycles and test for normal operation  
E.4 Salt mist test  
Submit engine and chassis mounted components tested under 4.4.5 to a salt mist test in accordance with IEC 
60068 -2-11, for a period of 96 h and after test for normal operation.  
E.5 Contamination  
Mount the component in its normal operating attitude and test in ac cordance with test Rb of IEC 60068 -218 by 
applying a spray, using the following materials at the temperatures stated:  
a) At 20 ± 5 °C:  
1) 1,1,1 -trichloroethane (BS 580);  
2) White spirit (KS 666);   
10 © UNBS 2020  – All rights reserved  
 3) Unleaded petrol (KS 2060);  
4) Methanol (BS 506 -1). 
b) At 70 ± 3 °C:  
1) Dies el fuel (class A1) (KS 1309 -1); 
2) Engine oil (KS 1099);  
3) auto -gearbox/power steering oil (KS 1507);  
4) Manual gearbox/hypoid oil (KS 1507);  
5) Grease: lithium soap based;  
6) brake/clutch fluid;  
7) Hydraulic power brake fluid;  
8) Ethyle ne gly col anti -freeze (50 % solution)  
Visually inspect the component for surface deterioration and test for normal operation.  
E.6 Driving rain: chassis mounted components  
The test chamber shall have the dimensions and 6 nozzle arrangements as shown in Figu re 2. Each nozzle 
includes a jet which shall emit a solid cone spray (a solid cone spray is defined as one where the water within 
the spray is evenly distributed). Each nozzle shall pass (455 mL/min to 758 mL/min) of water. Mount the 
component in the test chamber in its normal operating attitude, positioned so that the centre of the unit is 
approximately 6 in (152 mm) above the centre of the test chamber floor and so that the spray from all the 
angled jets impinges upon the component. Leave any drain holes open and fit all appropriate electrical leads 
and grommets. Where applicable, protect mounting and mechanical connections to simulate normal service 
conditions. Subject the component to continuous water spraying (maximum water temperature 40 °C) for a 
period of 25 h. Allow the test unit to drain for 1 h.  
At the conclusion of the preceding test, test the component for normal operation. The component shall have 
passed the test unless small globules of water are present in the enclosure in such aggregate quant ity as to 
be detrimental to the life or operation of the component. Materials used for the enclosure, including gaskets, if 
any shall be unaffected by water  
NOTE 1 The component may subsequently be subjected to a prolonged storage and/or endurance test. An y such test 
requirements should be stated in the product specification.  
NOTE 2 A practical evaluation technique is to remove the component after completing the above procedure and whilst 
maintaining the same mounting attitude, transferring to a low tempera ture environment to cause water freezing, and then 
test for normal operation  
E.7 Mycological  
Test in accordance IEC 60068 -2-10 as follows:  
Wash the exterior of the component and the spraying equipment with a 2 % solution of liquid detergent, rinse 
in clean  water and thoroughly dry.  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  11 
 Position the component together with any relevant ancilliary equipment in its vehicle attitude with all its 
connections made, in an environmental chamber for 24 h. maintain the test chamber at a temperature of 32 
°C with relative  humidity of not less than 95 % without precipitation.  
Spray the component with a suitably labeled aqueous solution of fungus spores from the following list. It is 
sufficient that each part be wetted with solution.  
Maintain the component in the environment al conditions detailed above in darkness for a period of 28 days.  
Test the component for normal operation.  
The following fungus spores are required in aqueous solutions, as specified 2):  
a) Aspergillus niger;  
b) Aspergillus amstelodami;  
c) Paecilomyces va riotii;  
d) Stachybotrys atra;  
e) Chaetomium globsum;  
f) Penicillium brevicompact um; 
g) Penicillium cyclopium   
12 © UNBS 2020  – All rights reserved  
 
 
Figure 2 — Driving rain test: test cabinet nozzle arrangement (6 nozzles, 4 angled, 2 horizontal)  US 2277 -2: 2020  
© UNBS 2020  – All rights reserved  13 
 Bibliography  
[1] BS 506 , Methanol for industria l use.  
[2] BS 506 -1, Specification for methanol.  
[3] BS 580 , Specification for trichloroethylene  
[4] BS 245 , Specification for mineral solvents (white spirit and related hydrocarbon solvents) for paints and 
other purposes  
[5] BS 3G 100 -4, Specification for  general requirements for equipment for use in aircraft - Electrical 
equipment.  
[6] BS 3G 100 -2, Electromagnetic interference at radio and audio frequencies.  
[7] KS 1586 -1, Specification for radio interference measuring apparatus and measurement methods - Part 1 - 
Radio disturbance and immunity measuring apparatus  
[8] KS 875 , Method of test for rubber vulcanized - Determination of the effect of liquids  
[9] KS 1309 -1 Specification for diesel fuels - Part 1: Automotive gas oil.  
[10] KS 2060 , Specification for unleaded petrol (gasoline) for motor vehicles.  
[11] CD/ENG/17:2009,  Maximum road speed limiters for motor vehicles — Part 1: Specification for installed 
requirements  
[12] DEF STAN 59 -41-3 (issue 2) Electromagnetic compatibility - DRSO2, Radiated susceptibil ity. 
[13] DIN 57879:1981 -3, Radio interference suppression for motor vehicles, vehicle equipment and internal 
combustion engines - Measurements of vehicle equipment   
 US 2277 -2: 2020  
© UNBS 2020 – All rights reserved  15 
 Certification marking  
Products that conform to Uganda standards may be marked with Ugand a National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certif ication mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further par ticulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 US 2277 -2: 2020    
 
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