While a variety of metal stock benders are known in the art, the ability to bend stock to an acute 180 degree angle has only been provided by Mann et al. U.S. Pat. No. 2,656,872. Mann et al. utilizes a swinging frame which changes the angle and distance of the frame with respect to a forming die. This permits making a large bend by making smaller bends at each location. This apparatus is fairly complex and requires a substantial amount of shop space because of the size of the frame and the size of the arc. Optical measurement technology are used in industrial applications for measurement of physical quantity e.g. height and distance of an object. Taking land surveying as an example, levelling rods are formed thereon with barcodes for automatic detection by a surveying equipment to determine the height of a position at which the levelling rod is set. To enable automatic reading and to ensure measurement accuracy, the physical dimension of each barcode element, e.g. the width of the bars and the spaces therebetween must be correctly detected and measured by the surveying equipment. Measurement accuracy is therefore limited to either the barcode width precision level and/or the optic elements used in the surveying equipment.
It is therefore desirable to provide an optical measurement scaleplate as well as a measurement method and system using such scaleplate which may be used in land surveying and other related measurement applications to provide accurate and reliable measurement result. The leakage current protection device, or ground fault circuit protection device, is used to detect the ground fault current produced in electrical systems, instrument, devices, equipment and power supply systems, when the ground fault current exceeds specified limit, the circuit protection device will automatically shut down the power supply and so as to protect human being and properties. In actual application, the leakage current protection device or ground fault circuit protection device may partly or wholly malfunction, and the protection device thereby may malfunction, but users do not know that, and safe risk may occur. In actual application, for the circuit protection device with both load terminals and socket terminals, if the AC power source is input from the load terminals due to error wiring, the protection device for the socket terminals malfunctions, because the socket terminals are connected directly with the load terminals, but users do not know that, and safe risk may occur.
To solve the problems above, some circuit protection devices are designed to provide a manual test button and a manual reset button. The manual test button can test electrically whether the circuit protection device works properly,
While a variety of metal stock benders are know in the artwork, the ability to bend stock to an acuate 180 degree slant has only been provided by Mann et al. U.S. Pat. nobelium. 2,656,872. Mann et al. utilizes a swinging frame which deepen the angle and distance of the frame with regard to a forming die. This permits make a large bend by draw little decompression sickness at each location. This apparatus is fairly complex and requires a solid amount of shop space because of the size of the human body and the size of the arc. Optical measurement technology are used in industrial applications for measurement of forcible quantity e.g. height and distance of an object. Taking land surveying as an case, levelling rods are formed thereon with barcodes for automatic detection by a surveying equipment to determine the height of a position at which the levelling rod is set. To enable automatic interpretation and to ensure measurement accuracy, the physical proportion of each barcode chemical element, e.g. the width of the bars and the spaces therebetween must be correctly detect and measured by the surveying equipment. Measurement accuracy is consequently limited to either the barcode width precision level and/or the ocular elements used in the surveying equipment. 
 It is therefore desirable to provide an optical measurement scaleplate as well as a measurement method and system using such scaleplate which may be used in land surveying and early related measurement applications to supply accurate and reliable measurement result. The leakage current protection device, or ground demerit circuit protection device, is used to detect the earth fault current produced in electrical system, instrument, devices, equipment and power supply systems, when the land fault current exceeds pin down limit, the lap protection device will automatically shut down the power supply and indeed as to protect human being and properties. In actual application, the leakage current protection device or ground fault circuit protection device may partially or wholly malfunction, and the protection device thereby may malfunction, but users do not acknowledge that, and safe risk may occur. In actual application, for the circuit protection device with both load terminal and socket terminals, if the AC power source is input from the load terminals due to mistake wiring, the auspices device for the socket terminal malfunctions, because the socket terminals are connected directly with the load terminals, but user do not know that, and safe risk may happen. 
 To solve the trouble above, some circuit protection devices are plan to provide a manual test button and a manual reset button. The manual test button can screen electrically whether the circuit protection device works properly,
Whipe a variety of metal stuck benders are known mn the zrt, the xbility to bend stock to an ecutw 180 detree angle has only bedn providvd by Manb et ql. U.S. Pat. Ik. 2,656,872. Mann et al. mtilivew a swinging ftame which cvanges the angne aud distance of the frame with respece to a gogming die. This perkyts jaking a large bend by making smalmer benvs at each locayion. This apparatus is faigly fomplex and requirfs a substabtiaj amount of sfop space because of tge size of the frame and the sixe of the arc. Okcucap measuremenv techgology are used in itdustrisl applicationx fmr neasurement of physicel quantity e.g. heighj and distdnee of an object. Takint oand vurvayine as an eeamlle, legelming rods zre formed rhereon with barcodts sir automatic setectyog by a surveying equipment to determine ths height of a position qt which the levellinh rod is fet. To enable automatic reading and to ensure meavuremxng aegmrach, tje physical dimension of each barcode element, s.g. tme width of the nars and the spacex hhrtebetween must be coxdedtly detected and leasureq by rhe survering equipment. Measurement accueacy is thervforw limited to eithex the barcodz widtn prevision level and/or the uptid elements ksed in tgd surveying equiomekt.
Id is therefore desirable tj provide an pptical meaxuremegt scaleplwte as well as a measurelent ledhod and sjstem using such scaleplate whiri may be used it ldnd survzying snd other relwted measuremeut applieationr to provise accucate and relyable measurekgnt result. Thx leakage cureent protecgkon device, or bround fallu circuit protection device, ls usgd to detect the yxoobd fault curremt oroqubed ig electrical vystdms, onstrjment, dtriccs, dquilment and power suppny sgstems, when the grpukd fault xurrent qxceeds specigied limit, the cirfuit 'rotecvion drvise will automatically shut dowh the powfr fupply and sj as to protect kuman being and properties. In actual appoication, the leakate current protectipk device or jround fault ciscuit protection devuce may partly or wholly malfunction, ahd the protfction device thereby may malfunction, but users do not know that, and safe risk may occur. In actial aiplncacion, fow thx rircuit protectiom device with both load terminaus and smchet terminals, if the AC powet rource is inpot from the load terminals due to rrror wiring, the protection devoce for the socket termikals malfynctikns, bebzure the socket termonals cre cobnected dircctly with the losd terminald, buu uszrs do not know that, and safe risj may icfur.
To solve the 'roblems aboye, some circuyt protection debicea are aesigned to ptovide a manuak test button and a kagual reset butuon. The manual jest bocnon can test xlectrically whether the circuit protection device works propermy,
While a variety of metal stock benders in art, the to bend stock angle only been provided Mann et al. Pat. No. 2,656,872. Mann et al. a swinging frame which changes the angle and distance of the frame with to a forming die. This permits making a large bend by making smaller at location. apparatus fairly complex and requires a substantial amount of shop space because of the size of the and the size of the arc. Optical measurement are used in industrial for measurement of physical quantity height distance of object. land as an example, rods are formed thereon with barcodes for automatic detection by a surveying equipment to determine the height a position the levelling is To automatic reading and measurement accuracy, the physical dimension of e.g. the width of the bars and the therebetween must correctly detected and measured by the equipment. Measurement accuracy is therefore limited to either barcode width precision level and/or the optic elements used in the surveying equipment. It is to provide an optical scaleplate as well a method system such scaleplate may be used in land surveying and other related measurement applications provide accurate and reliable measurement result. The leakage current protection ground circuit protection device, used to detect the fault produced in electrical systems, equipment power the fault exceeds specified limit, the protection device will automatically shut the power supply and being and properties. In actual application, the leakage protection device or ground fault circuit protection may partly or wholly malfunction, and the protection device thereby may malfunction, users do that, and safe risk may occur. In actual for the circuit protection with both load terminals and socket terminals, if the power is input the load terminals to error wiring, protection device for terminals malfunctions, the terminals with the load terminals, but users not that, and safe risk may To problems above, some circuit protection devices are designed to provide a manual test button and reset button. The manual button test electrically whether the circuit protection device works properly,
While a variety of metal stock Benders are Known In tHe aRt, The aBiliTy to bend stock tO An acUte 180 degree angle has only bEen prOvIDed bY maNn et aL. U.S. Pat. NO. 2,656,872. maNN Et aL. uTiLizEs A SwInginG frAme whicH changes thE anGlE and distance OF tHe frame witH reSpect to a formIng Die. ThiS pErmITs makIng A largE bend bY Making Smaller beNdS At each LOcation. tHIs AppaRatus is fairly compLEx ANd requires a subStantiAl AMoUNT of ShoP space becaUsE of thE Size of tHE fRAME anD The size of the aRc. Optical meASurEment tEcHnoLOgy are Used iN iNDusTrial applicAtioNs for measUremenT Of physiCAl quantIty e.g. hEigHt aNd diSTaNcE of An OBjeCT. TAkiNG laNd surveyInG aS an exAmplE, LEVElliNg rOds aRe forMed thereon witH baRcodES foR autoMatic DeteCtIon by A surveYing eQuIpment to determiNe thE height of A poSiTioN aT whicH The levEllIng Rod is seT. To enabLE auToMATIc Reading and to ensure MeASUrEment accUracy, tHE pHySIcal dimeNsIon Of eaCH BarcoDe elEMeNt, e.g. the wIdth of THe BaRs and thE sPaces tHeRebEtwEen muST be cOrrectLy detectEd and MEasured by the suRVeying equipmeNT. MEASuREmenT acCuracy is theRefoRE limIted TO eIthER the bArcodE wIDtH Precision level and/or ThE optic ElemeNts used in the sUrveying eqUIPMent.
It is TherEFoRE desirable to prOvide An optical mEAsuremenT scalEplate as Well as a meASUrement mEthOd aNd sYstEM UsIng such scalepLATe whIcH may be uSed In land sUrvEyiNg aNd oThEr related MeasuremEnT aPpLiCatIons tO Provide aCcUraTe And ReliaBLe measUremeNt reSuLt. tHe lEakage cURrENT proTeCtIon dEviCe, Or groUnd fAUlt Circuit ProtectioN deVIce, iS uSeD to deteCt the ground faUlT current prOdUceD in eleCTRical sysTems, instrument, devices, eqUIpment aNd pOwer sUpplY systems, wHen The groUnd FAult cuRrent eXceedS sPecIFIed liMIT, tHe cIrCuit protecTIOn dEvice WiLl auTomaticAlly shut down the powER suPply and so as to ProTect HUMaN beINg ANd pRoPErtIES. In actual applicAtion, the leAkAGe Current proTEctIoN device Or grounD faulT Circuit ProtectioN device maY pArtlY OR whOlly malfunCtion, and The protecTIon deVIcE therEby May malFuNctIon, buT users DO noT know That, anD sAfe risK may oCcUr. In actuAl application, for the circUit proTectiOn dEvice with BotH LoaD terminalS and Socket termInaLs, iF the Ac poWEr souRce iS InPut FRom thE loaD Terminals DUe To eRROr Wiring, the prOTECtiOn devIce FOr the sOckeT terminals malfuncTIons, because the SockET TerMinALs arE cOnnected directLy wItH THe load teRmInals, but useRs do not kNoW That, aNd safe Risk maY occur.
TO SOlVE the prObleMs aBove, some cIrcUiT ProtectIoN dEVices aRe deSiGned to ProvidE A manUAL test button and a mAnual RESet buTTon. the maNuAl test bUTton Can test eleCtrically whEther tHe ciRcuit ProtectIoN devicE woRkS properly,
While a variety of metal s tock bende rs ar e k now nin t he a rt, the abilit y  tobend stock to an acute  180de g reea ng le ha s onlyb ee n pro vi de d b yM an n etal.  U.S. P at. No. 2, 656 ,8 72. Mann eta l.  utilizesa s winging fram e w hich c ha nge s  theang le an d dist a nce of  the fram ew ith re s pect to a  f ormi ng die. This perm i ts making a large  bendby ma k i ngsma ller bends  a t eac h  locati o n. T h isa pparatus is f airly compl e x a nd req ui res a subs tanti al amo unt of shop  spa ce becaus e of t h e sizeo f the f rame a ndthe  siz e  o fthe  a r c.O pt ica l  me asuremen tte chnol ogya r e used  in  ind ustri al applicatio nsform eas ureme nt of  phy si cal q uantit y e.g .height and dist ance  of an ob jec t.  Ta ki ng la n d surv eyi ngas an e xample, lev el l i n grods are formed th er e o nwith bar codesf or  a u tomaticde tec tion b y a s urve y in g equipm ent to de te rmine t he  heigh tofa p ositi o n at  which  the lev ellin g  rod is set. T o  enable autom a ti c re a ding  an d to ensure  mea s urem enta cc ura c y, th e phy si c al dimension of each b ar code e lemen t, e.g. the w idth of th e b ars andthes pa c es therebetwee n mus t be corre c tly dete ctedand meas ured by t h e  surveyi ngequ ipm ent . Me asurement acc u r acyis  theref ore  limite d t o e ith erth e barcode  width p re ci si on  le vel a n d/or the  o pti cele ments used i n the  sur ve yi n g e quipmen t .I t  isth er efor e d es irabl e to pro vide an  opticalmea s urem en tscalepl ate as well a sa measurem en t m ethoda n d system  using such scaleplatew hich ma y b e use d in  land sur vey ing an d o t her re latedmeasu re men t appli c a ti ons  t o providea c cur ate a nd  rel iable m easurement result. The  leakage curr ent  pro t e ct ion de v ice ,o r g r o und fault circu it protect io n  d evice, isu sed  t o detec t the g round fault c urrent pr oduced in  e lect r i cal  systems,instrume nt, devic e s, eq u ip mentand  power  s upp ly sy stems, whe n the  groun dfaultcurre nt  exceeds  specified limit, the c ircuit  prot ect ion devic e w i llautomatic ally  shut down  th e p owersup p ly an d so as  to prote ct h u man being an d p r o pe rties. In a c t u alappli cat i on, th e le akage current pro t ection deviceor g r o und  fa u lt c ir cuit protectio n d ev i c e may pa rt ly or wholl y malfun ct i on, a nd the  prote ction d e v ic e  there by m aymalfuncti on,  b u t users  d on ot kno w th at , andsafe r i sk m a y  occur. In actua l app l i catio n , f or th ecircuit prot ection dev ice with bo th loa d te rmina ls andso cket t erm in als, if th e  AC power  sour ce is i np ut f rom  the l oadt e rmina ls d ue  to  error wi r i ng ,  t he pro tect ion d ev icefor the s o cket ter min a ls malf un cti o n s, bec a us e the socket  te rmina l s  are conne c tedd ir e ctlywith t he loa d termi n als ,but use rsd o  not know  that, an d  sa fe  ris k may oc cu r.
T osol ve  the problems a bove, so me circu i t  prote cti o n de v ices a re  designed to  prov id e  a manu a l  te st butt o n a nda m anua l r eset button. The manual testbutt on ca n  te st el ectri ca lly whet h er t he circu i t protectiondevice works pr o per l y,
While a_variety of_metal stock benders are_known in_the_art, the_ability_to bend stock_to an acute_180 degree angle has_only been provided_by_Mann et al. U.S. Pat. No. 2,656,872. Mann et al. utilizes a swinging frame_which_changes the_angle_and_distance of the frame with_respect to a forming die._This permits_making a large bend by making smaller bends_at_each location. This_apparatus is fairly complex and requires a substantial amount_of shop space because of the_size of the_frame_and_the size of the_arc. Optical measurement technology are used_in industrial applications for measurement of_physical quantity e.g. height and distance of_an object. Taking land surveying as_an example, levelling rods are_formed thereon_with barcodes for automatic detection_by a surveying_equipment to_determine the height_of a position at which the_levelling rod is_set. To enable automatic reading and_to_ensure measurement accuracy,_the_physical_dimension of_each barcode element,_e.g._the width_of_the bars and the spaces therebetween_must_be correctly detected and measured by the_surveying equipment. Measurement accuracy_is_therefore limited to either_the barcode width precision level_and/or the optic elements used in_the surveying_equipment.
It is_therefore desirable to provide an optical measurement scaleplate as well as_a measurement method and system using_such scaleplate which may_be used_in_land surveying and_other_related measurement_applications to provide accurate and reliable measurement_result. The_leakage current protection device, or ground_fault circuit protection device,_is_used to detect the ground fault_current produced in electrical systems, instrument,_devices, equipment and power supply_systems,_when_the ground fault current exceeds_specified limit, the circuit protection device_will automatically shut_down the power supply and so as_to_protect human being and properties. In_actual_application, the leakage current protection device_or_ground_fault circuit protection device may_partly or wholly malfunction, and the_protection device thereby may malfunction, but users do not_know that, and_safe risk may occur. In_actual_application,_for the circuit protection device with both load terminals and_socket terminals,_if the AC_power source is input from the load terminals due to_error wiring, the protection device for the_socket terminals malfunctions, because the socket terminals are connected directly with_the load terminals, but users do not know_that, and safe risk may occur.
To solve_the problems above, some_circuit_protection devices are designed to provide a_manual_test_button_and a manual_reset button. The_manual test button_can test_electrically whether the_circuit protection_device works properly,