1、DEUTSCHE NORM June 1999 Precision dial indicators Part 3: Analogue indicators with electrical limit contacts DIN 879-3 - ICs 17.040.30 Supersedes November 1975 edition. Prfen geometrischer Gren - Feinzeiger - Teil 3: Mit mechanischer Anzeige und elektrischen Grenzkontakten In keeping with current pr
2、actice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker. Foreword This standard has been prepared by Technical Committee Eindimensionale Langenprftechnik of the Normenausschu Technische Grundlagen (Fundamentals
3、 in Technology Standards Committee). Amendments This standard differs from the November 1975 edition as follows. a) Statistical concepts have been harmonized with the June 1999 edition of DIN 879-1 b) Dielectric strength is no longer specified. c) The standard has been editorially revised. Previous
4、edition DIN 879-3: 1975-1 1 All dimensions are in mm. 1 Scope This standard specifies requirements for and the verification of precision dial indicators as in DIN 879-1 but which also have electrical limit contacts. 2 Normative references This standard incorporates, by dated or undated reference, pr
5、ovisions from other publications. These normative references are cited at the appropriate places in the text, and the titles of the publications are listed below. For dated references, subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in
6、 it by amendment or revision. For undated references, the latest edition of the publication referred to applies. DIN 102 DIN 879-1 DIN 1319-1 DIN 1319-2 Reference temperatures for measuring instruments and workpieces Precision dial indicators - Part 1 : Analogue indicators Basic concepts in metrolog
7、y - General concepts Basic concepts in metrology -Terminology relating to the use of measuring instruments Continued on pages 2 to 4. Translation by DIN-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text. No pari of this translation may be re
8、produced without the prior permission of Ref. No. DIN 879-3 : 1999-0 V Deutsches Institut fur Normung e VI Berlin uth Verlag GmbH, D-10772 Berlin, hac the exclusive right of sale for German Standards (DIN-Normen) English price group 05 - Sales No Page 2 DIN 879-3 : 1999-06 DIN 2257-1 Terminology use
9、d in dimensional metrology - Units, activities, checking instruments - Metro- logical concepts DIN 32876-1 Electrical length measurement with analogue data acquisition - Concepts, requirements and testing l International Vocabulary of Basic and General Terms in Metrology (VIM) = Internationales Wrte
10、rbuch der Metrologie. 2nd GermadEnglish ed. Edited by DIN Deutsches Institut fr Normung e.V., 1994. I) 3 Concepts Forthe purposes of thisstandard, the conceptsdefined in DIN 879-1, DIN 1319-1, DIN 1319-2, DIN 2257-1 and l apply, as well as the following concepts. 3.1 A dial indicator as in DIN 879-1
11、 which also has at least two adjustable limit contacts that can be used to divide the measuring range into at least three sub-ranges, or classes (e.g. good, requires correction and sub- standard). Precision dial indicator with electrical limit contacts 3.2 Repeatability For the purposes of this stan
12、dard, the difference between the extreme values at which a change in class is signalized (cf. subclause 3.1), for a given uncertainty of measurement (repeatability limit) and with the plunger moving in the same direction (cf. DIN 32876-1). 3.3 Repeatability limit For the purposes of this standard, t
13、he extreme value specified for the repeatability of a dial indicator. Desig- nated by fgw. 3.4 Hysteresis error For the purposes of this standard, the difference between the extreme values at which a change in class is signalized, for a given uncertainty of measurement (repeatability limit) and for
14、both directions of plunger movement (cf. DIN 32876-1). Designated by fgu. 3.5 Shift (of indication) Difference between the readings before and after adjustment using the fine adjustment screw. 4 Dimensions and designation 4.1 Dimensions Dimensions shall be as specified in DIN 879-1. 4.2 Designation
15、Designation of a precision dial indicator as in this standard with 1 O pm scale intervals (1 O) and two electrical contact limits (2 G), with connecting cable: Dial indicator DIN 879 - 10 - 2 G 5 Requirements 5.1 General For indicators with scale intervals greaterthan 1 pm, the values in table 1 sha
16、ll be complied with in any indicator position and shall not be exceeded at any point within the measuring range. For indicators with scale intervals of 1 pm or smaller, the specified limits of error, G, and the hysteresis error, fu, apply for the vertical position with the plunger pointing downwards
17、; in other positions, these values may be exceeded by 30 %. 5.2 Reference temperature The reference temperature shall be 20 “C, in accordance with DIN 102. I) Obtainable from Beuth Verlag GmbH, Burggrafenstrae 6, 10787 Berlin, Germany. Page 3 DIN 879-3 : 1999-06 Limit of hysteresis error, f, Table 1
18、: Characteristics of dial indicators with limit contacts up to 1 pm over 1 pm 1 0,s Characteristic 1 Limit of error in one direction of movement (retracting plunger) over the entire measuring range, Gei) Limit of error in both directions of movement (retracting and extending plunger) over the entire
19、 measuring range, Geesi) 13 Permissible errors, in scale intervals For intervals I For intervals 1 13 Repeatability limit, r Il I 0,s I 0,7 I 0,7 Limit of error in one direction of movement (retracting plunger) over a range of any ten scale divisions, Gti) Repeatability limit, fgw Limit of hysteresi
20、s error, fe, I 0,s I 0,s i) The limits of error shall be met at any randomly selected setting within the measuring range. Any doubling of permissible errors is precluded because these values apply for any position, including those at an extreme value. 5.3 Measuring force and hysteresis error of meas
21、uring force The measuring force with the plunger in the vertical position pointing downwards shall not exceed 3 N. With the plunger pointing vertically upwards, the force shall be at least 0,4 N. Within the measuring range, the difference between the minimum force and maximum force, in the same dire
22、ction of movement as the plunger, shall be no greater than 1 N. The hysteresis error of the measuring force, flc, shall not exceed 0,5 N at any setting within the measuring range. 5.4 Shift When the range of the fine adjustment screw is fully utilized, the difference in readings shall not exceed one
23、 scale interval. 5.5 Additional requirements The requirements specified in clause 5 of DIN 879-1 also apply to dial indicators as in this standard. 6 Verification 6.1 General Verification shall be carried out as specified in clause 6 of DIN 879-1 to ensure the values specified in clause 5 of the pre
24、sent standard are met. For verification, the limit contacts shall either be set outside the measuring range or drawn by the pointer across the entire range, depending on the indicator design. 6.2 Repeatability Set the limit contacts at any random point, with the dial indicator connected to a suitabl
25、e indicating instrument having indicator lamps. Carry out five measurements at each limit and establish the greatest difference in readings. Compare this difference with the limits specified in table 1. 6.3 Hysteresis error Determine the switching hysteresis error at each limit contact as the differ
26、ence between the indication with the plunger retracting and that with the plunger extending. Carry out five measurements at each limit and establish the mean. During testing, the pointer deflection shall be across at least five scale intervals in the direction of measurement. Compare values with tho
27、se given in table 1. 6.4 Shift Turn the adjustment screw to its final position and take the reading. Then, turn the screw all the way to the other end position and again take the reading to check the shift in indications. Page 4 DIN 879-3 : 1999-06 7 Items to be supplied with indicators Since the di
28、al indicators with electrical contacts on the market have many different types of switching system, each indicator as in this standard shall be supplied with a connecting cable, instructions for use and a circuit diagram giving the main electrical characteristics (operating voltage, operating curren
29、t, etc.). Appendix A Information on use Care should be taken to ensure that the electrical data provided by the manufacturer is complied with as far as possible. If the operating voltage is too low, the repeatability will be reduced, and if it is too high, the life of the contacts will be shortened.
