1、ANSI/EIA RS-448-4 - 1980 APPROVED OCTOBER 6, 1980 EIA STANDARD STANDARD TEST METHODS FOR ELECTROMECHANICAL SWITCHES (Test Methods for Logic (TTL) Level Endurance and Low Level Endurance) RS448.4 (Addendum No. 4 to RS-448) NOVEMBER 1980 Engineering Department ELECTRONIC INDUSTRIES ASSOCIATION - EIA 4
2、48-4 0 3234b00 0069093 4 M NOTICE EIA Engineering standards are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, faci- litating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with
3、 minimum delay the proper product for his particular need. Existence of such standards shall not in any respect preclude any member or non-member of EIA from manufacturing or selling products not conforming to such standards, nor shall the existence of such standards preclude their voluntary use by
4、those other than EIA members, whether the standard is to be used either domestically or internationally. Recommended standards are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA does not assume any liabilit
5、y to any patent owner, nor does it assume any obligation whatever to parties adopting the recommended standards. This EIA Recommended Standard is considered to have international stan- dardization implications, but the IEC (or ISO) activity has not progressed to the point where a valid comparison be
6、tween the EIA Recommended Standard and the IEC (or ISO) Recommendation can be made. Published by Engineering Department 2001 Eye Street, N.W., Washington, D.C. 20006 . ELECTRONIC INDUSTRIES ASSOCIATION Copyright 1980 ELECTRONIC INDUSTRIES ASSOCIATION All rights reserved PRICE: $4.00 Printed in U.S.A
7、. EIA 448-4 80 3234b00 00b9094 b = RS-448-4 Addendum 4 STANDARD TEST METHODS FOR LOGIC (TTL) LEVEL ENDURANCE AND LOW LEEL ENDURANCE (From EIA Standards Proposals No. 1424 and No. 1425 formulated under the cog- nizance of EIA Working Group P-5.9 on Non-Sensitive. Pushbutton and Keyboard Switches.) Th
8、is Standard is Addendum No. 4 to RS-448 covering logic level and low level endurance. The following test methods are included: (1) Logic (TTL) Level Endurance - Method 17 (2) Low Level Endurance - Method 18 -i- - EIA 448-4 80 m 3234600 0067095 8 I- RS-448-4 Addendum 4 INDEX OF TEST METHODS ELECTROME
9、CHANICAL SWITCHES can be found in EIA RS-448: Method 1 - Switch Resistance Method 2 - Capacitance Method Method Method 7 - Overload Method 8 - Electrical Endurance Method 9 - Mechanical Endurance Method 10 - High/Low Temperature Operation Method 11 - Actuator/Mounting Bushing Resistance Method 12 -
10、Shock Test (Specified Pulse) Method 13 - Monitoring Contact Chatter Method 14 - Sand and Dust 5 - Strength of Mounting Mass 6 - Terminal Temperature Rise This addendum forms part of EIA Standard RC-448,. The following Test Methods 4 .6 9 10 12 16 20 21 22 23 30 31 The,following Test Method can be fo
11、und in EIA RS-448-1: Method 15 - Contact Bounce 1 The following Test Method can be found in EIA RS-448-2: Method 16 - Environmental Effects for Machine Soldering The following Test Methods can be found in EIA RS-448-3: Method 3 - Chromaticity Method 4 - Transmittancy (Luminance) The following Test M
12、ethods can be found in EIA RS-448-4: Method 17 - Logic (TTL) Level Eildurance Method 18 - Low Level Endurance 1 1 2 1 1 - EIA 448-Li 0 m 3234b00 00b909b T m RS-448-4 Addendum 4 Page 1 METHOD 17 TEST METHOD FOR LOGIC (TTL) LEVEL ENDURANCE 1. PURPOSE The Logic Level Endurance Test is a measure of the
13、ability of a switch to control electrical loads in which the applied voltage exceeds the melting voltage of the switch contact material and is less than the arcing voltage and arcing current. Electronic logic circuits have defined interface signal voltages. Logic “O“ is a signal voltage between O an
14、d 0.9 volts. Logic “1“ is a signal voltage greater than 2.4 volts and less than 5.5 volts. 2. TEST CONDITIONS Each pair of switch contacts shall be tested using a 5.0 + 0.5 V dc, 10 + 1 mA resistive load. During each closure of the contacts, the voltage drop across the switch terminals shall be moni
15、tored for a .duration of no less than 50% of each contact static closure. The switch contacts need not be monitored until 10 milliseconds after the initial contact closure to exclude any contact bounce. During each opening of the contacts, the voltage drop across the switch terminals shall be monito
16、red for a duration of no less than 50% of each contact opening. A voltage of 2.1 volts or greater across the switch terminals shall constitute a contact lmissll (failure to properly close the circuit). A voltage drop of less than 90% of the open-circuit voltage shall constitute a contact %tickt1 (fa
17、ilure to properly open the circuit). The monitoring device shall either record the number of contact closures at which %ticks“ and/or “misses“ occur, or discontinue the test when “sticks1f and/or “misses“ occur. 3. PROCEDURE Each pair of switch contacts shall be operated for the number of cycles and
18、 at the rate of actuation specified in the detail specification with the required test load applied. The test shall be performed under the environmental conditions specified in the detail specificaticn. EIA 448-4 0 M 3234b00 OOb9097 L M RS-448-4 Addendum 4 Page 2 4. SUMMARY The following details sha
19、ll be specified in the detail specification: 4.1 4.2 The rate of actuation. The number of cycles of operation. 4.3 The number of allowable contact tlrnissesll. 4.4 The number of allowable contact %ticks“. 4.5 The environmental conditions. NOTE: In actual applications, electronic logic circuits may u
20、tilize different voltages, currents, and/or interface signal voltages, and should be care- fully analysed to determine the suitability of this logic level endurance test method. I ,- qc 6 e a EIA 448-4 80 m 3234600 00b9098 3 = RS-448-4 Addendum 4 Page 1 METHOD 18 LOW LEVEL ENDURANCE 1. PURPOSE The L
21、ow Level Endurance Test is a measure of the ability of a switch to control electrical loads which have insuffiecent energy to cause any physical change in the switch contacts. 2. TEST CONDITIONS Each pair of switch contacts shall be tested at 30 mV maximum, 10 mA maximum resistive load. During each
22、closure of the contacts, the voltage drop across the switch terminals shall be monitored for a duration of no less than 50% of each contact static closure. The switch contacts need not be monitored until 10 milliseconds after the initial contact closure to exclude any contact bounce. During each ope
23、ning of the contacts, the voltage drop across the switch terminals shall be monitored for a duration of no less than 50% of each contact opening. A voltage drop of 50% of the open circuit voltage or greater across the switch terminals shall constitute a contact “miss“ (failure to properly close the
24、circuit). A voltage drop of less than 90% of the open circuit voltage shall constitute a contact “stick“ (failure to properly open the circuit). The monitoring device shall either record the number of contact closures at which “sticks“ and/or “misses“ occur, or discontinue the test when %ticks11 and
25、/or “misses“ occur. 3. PROCEDURE Each pair of switch contacts shall be operated for the number of cycles and at the rate of actuation specified in the detail specification with the required test load applied. The test shall be performed under the environmental conditions specified in the detail spec
26、ification. RS-448-4 Addendum 4 Page 2 4. SUMMARY The foltowing details shall be specified in the detail specification: 4.1 4.2 The rate of actuation. The number of cycles of operation. 4.3 The number of allowable contact ttmissestt. 4.4 The number of allowable contact %tickstt. 4.5 The environmental conditions. NOTE: Because applications vary, they should be carefully analysed to determine the suitability of this low level endurance test method. .
