ASTM_F_1689_-_05_2012.pdf

Designation:F168905(Reapproved 2012)Standard Test Method forDetermining the Insulation Resistance of a MembraneSwitch1This standard is issued under the fixed designation F1689;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the insu-lation resistance of a membrane switch.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions:2.1.1 insulation resistancethe electrical resistance be-tween test points.2.1.2 leakage currentcurrent flow through the insulationbetween test points.2.1.3 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.2.1.4 test pointstwo preselected conductive points in acircuit loop,possibly including a switch.3.Significance and Use3.1 Insulation resistance is useful for design verification,quality control of materials,and workmanship.3.2 Low insulation resistance can cause high leakage cur-rents.3.3 High leakage currents can lead to deterioration of theinsulation or false triggering of the associated input device,orboth.3.4 Specific areas of testing are,but not limited to:3.4.1 Conductor/dielectric/conductor crossing point.3.4.2 Close proximity of conductors,and3.4.3 Any other conductive surface such as shielding ormetal backing panel.3.5 Insulation resistance measurement may be destructiveand units that have been tested should be considered unreliablefor future use.4.Interferences4.1 The following parameters may affect the result of thistest:4.1.1 Humidity,4.1.2 Contamination,4.1.3 Barometric pressure,and4.1.4 Temperature.5.Apparatus5.1 Electric Device,suitable to provide a constant prese-lected dc voltage and suitable electronic monitoring device tomeasure very small current levels(micro-ampere range),or5.2 Resistance Measuring Device,such as a megohm-meter,or equivalent that can provide a specified voltage.(This wouldreplace 5.1.)6.ProcedureVoltage Source Method(Fig.1)6.1 Pretest Setup:6.1.1 Connect test points of the switch assembly to thevoltage source.6.1.2 Connect leakage current measuring device in serieswith the voltage source.6.2 In-Process Test:6.2.1 Adjust voltage source to 100 VDC 6 10%or asspecified.6.2.2 Dwell for 60 s.6.2.3 Record leakage current.7.ProcedureMegohm Method(Fig.2)7.1 Pretest Setup:7.1.1 Connect test points of the switch assembly to themegohm-meter.7.2 In-Process Test:7.2.1 Adjust megohm-meter to 100 VDC 6 10%or asspecified.7.2.2 Dwell for 60 s.7.2.3 Record insulation resistance.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 1996.Last previous edition approved in 2005 as F168905.DOI:10.1520/F1689-05R12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.CalculationsVoltage Source Method Only8.1 Calculate the insulation resistance as follows:Insulation Resistance5 Applied Voltage/Leakage Current9.Report9.1 Report the following information:9.1.1 Temperature,9.1.2 Humidity,9.1.3 Barometric pressure,9.1.4 Applied voltage,9.1.5 Duration of applied voltage,9.1.6 Leakage CurrentVoltage Source Method only,9.1.7 Insulation resistance,9.1.8 Part number or description of switch,or both,9.1.9 Description of test points,9.1.10 Date of test,and9.1.11 Description of all equipment used(including sensi-tivity range).10.Precision and Bias10.1 The precision and bias of this test method are underinvestigation.11.Keywords11.1 insulation resistance;leakage current;membraneswitchASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you shouldmake your views known to