FREQUENTLY ASKED QUESTIONS FOR WEIGHTS AND SCALES

1) What is A/D Converter ?

ANS: This is analog signal to digital signal conversion for continuously varying voltage signals to discrete binary numbered values. A load cell output can be fed through an A/D converter to produce
a continuous stream of digitized information and send to digital indicator.

2) What is Accuracy ?

ANS: Precision in the measurement of quantities and in the statement of Physical characteristics. It is expressed as error as percent of specified Value. This term used to indicate the division or least count of weighing scale.

3) What are ambient conditions ?

ANS: The conditions of the medium surrounding the load cell like Humidity, Temperature , Pressure etc.

4) What is average piece weight?

ANS: On the counting scale, the amount of weight divided by number of Samples which comprised that weight. It is used to count pieces during normal operation.

5) What is Axial Load ?

ANS: A load applied to line concentric with primary axis.

6) What is Baud rate ?

ANS: A unit of communication processing speed in digital data  communication systems. The speed in baud is number of discrete conditions of signal events / second. If each signal events represents
only one bit condition, baud rate equals to bits/second.

7) What is beam (scale) ?

ANS: The indicating device of Lever Scale.

8) What is calibration ?

ANS: It is Electronic weighing to regulate the output of Electronic Circuit The comparison of  load cell against standard test loads.

9) What is manual calibration ?

ANS: Setting the POT fitted on circuit by technically trained person is manual calibration .

10) What is Auto-Calibration ?

ANS: An automatic procedure by means of software installed inside the weighing scale.

11) What is Corner Effect or Error ?

ANS: If the scale is not calibrated for each corner while manufacturing an error occurred at each corner that is corner effect or error.

12) What is checkweigher ?

ANS: A scale used to verify predetermined weight within prescribed limits.

13) What is CLASS III ?

ANS: Classes of scales used in commercial weighing not otherwise specified. Grain test scales, retail precious metals and semiprecious Gem weighing, animal scales, postal scales and scales used to determine laundry charges.

14) What is CLASS IIIL ?

ANS: Vehicle , axle-load , livestock , railway track scales , crane & hopper other than grain hopper scales.

15) What is creep ?

ANS: The change in load cell output occurring with time, while under load and with all environmental conditions and other variables remaining Constant usually measured with rated load applied and expressed as a Percent of Rated Output over a specific period of time.

16) What is capacity ?

ANS: Mass load weight of any of on weighing scale is its capacity .

17) What are different types of displays ?

ANS:

A) LED :- Light Emitting Diode
B) LCD :- Liquid Crystal Display
C) VFD :- Vacuum Florescent Display
D) Backlight LCD Display
E) Pixel & Color LCD Display.
F) Segmented LED Display

18) What is division ?

ANS: Value of smallest increment indicated or displayed by a scale.

19) What is dead load ?

ANS: The fixed force of weighbridge, platform and other load supporting
Structures of the scale. The value of which is to be permanently
Balanced or cancelled out in the weight or measuring system.

20) What is deflection ?

ANS: The change in length along the primary axis of the load cell between
No-load and rated load conditions.

21) What is dormant scale ?

ANS: A built in scale having self-contained under structure .

22) What is Dribble ?

ANS: In filling operations the weight value over which material is slowly handled to provide a more accurate cutoff .

23) What is e-verification scale division ?

ANS: Value of verification scale division specified by the manufacturer sets value for tolerances and accuracy class .

24)What is minimum verification scale divisions ?

ANS: The minimum scale division or value for which a device complies With applicable requirements. E.g. Bench or Counter Scales .

25) What is eccentric load ?

ANS: Any load applied parallel to but not concentric with primary axis.

26) What is Excitation ?

ANS: The voltage or current applied to the input terminals of the load cell.

27) What is fulcrum ?

ANS:A pivot point for lever is fulcrum load .

28) What is graduation ?

ANS: A mark on an instrument or vessel indicating degrees or quantity.

29) What is hysteresis ?

ANS: The maximum difference between load cell output readings for the same applied load. One reading is obtained by increasing the load from zero and the other reading is obtained by decreasing the load from rated load. Measurements should be taken as rapidly as possible to minimize creep.

30) What is Interface ?

ANS: A device or circuit that allows two units to communicate. Some of the Standard interfaces used in scale industry are 20 mA current loop ,BCD , RS-232 , RS-422 and RS-485.

31) What is intrinsically safe circuit ?

ANS: A circuit in which any spark or thermal effect is incapable of causing Ignition of mixture of flammable or combustible material in air under prescribed test conditions in its most easily ignitable concentration.

32) What is junction box ?

ANS: A box or enclosure used to join different runs of cable or wiring. It contains space and terminals for connecting and branching the enclosed conductors and adjustments to provide load cell trimming.

33) What is LED ?

ANS: A semiconductor light source that emits visible light or invisible
Infrared radiation.

34) What is Lever ?

ANS: A tool that transfers force equally with reduction or multiplication.

35) What is live load ?

ANS: The load applied to a scale base that is actually being measured by
the weighing system.

36)What is Load ?

ANS: The weight(mass)  or force applied to load cell .

37) What is Load Cell ?

ANS: A device which produces an output signal proportional to the applied weight or force. Types of load cells include beam, S-beam , Platform ,Compression and tension.

38) What is minimum dead load ?

ANS: Minimum dead load is specified for NTEP load cells. In a given application the dead load applied to each cell must be greater than or equal to the minimum dead load specified by the load cell manufacturer.

39) What are different types of Load Cells ?

ANS: Load cell comes in various size /shape / capacity / material.

40) What are single ended shear beam load cells ?

ANS: These are common in use for small , medium , large sized platform scales with beam at one end . Normally available for capacities of 5 kg to 7500 kg.

41) What are double ended shear beam load cells ?

ANS: It has double ended construction & is useful for high capacity weighing approximately 10000 kg or more.

42) What are S or Z type load cells ?

ANS: These load cells comes with Hanging & Weighing operation with range near about 5 kg to 50000 kg.

43) What are Canister type load cells ?

ANS: These are non-beam load cells for heavy weighing operations used in Rail or Road Weighbridges .

44) How can you explain load cell of different materials ?

ANS: These are Aluminum (for small capacity weighing ) , Stainless Steel (High Capacity Weighing) & Nickel-Alloy (for special application) systems like Tank , hopper and silo weighing. Magnetic induction based sensor used for high accuracy weighing and capacitance based sensors are used for non-commercial personal weighing of low accuracy sensors.

45) What is motion detection ?

ANS: A circuit used in an indicator to sense when the displayed weight data is changing at a greater rate than preset limits.

46) What is Non-Linearity ?

ANS: Maximum Deviation of calibration curve from a straight line drawn between no-load and rated load outputs .

47) What do you mean by output ?

ANS: The signal produced by a load cell where output is directly proportional to Excitation as volts per volts , mv /v , V / A etc .

48) What is Push-Button Auto Zero ?

ANS: Extension of AZM function of a digital weight indicator through the use of front panel push-button.

49) What is potted cell ?

ANS: A load cell which is environmentally sealed by strain gauge cavity with a material that protects it from environmental hazards like moisture.

50) What is remote sensing ?

ANS: A method of regulating the voltage to load cells .

51) What is repeatability ?

ANS: The maximum difference between load cell output readings for repeated loadings under identical loading and environmental conditions.

52) What is Resolution ?

ANS: The smallest change in mechanical input which produces a detectable change in the output signal.

53) What is RS-232 ?

ANS: A voltage based serial method of data communication used to transfer data between digital devices.Transmission distance should be upto 50 feet.

54) What is scale ?

ANS: A device for weighing , comparing  and determining weight of mass.

55) What is sensitivity ?

ANS: The ratio of change in output to change in mechanical input.

56) What is Serial Communication (Transmission) ?

ANS: A method of data transmission in which each bit of information is sent sequentially on a single channel .

57) What is set point ?

ANS: The point which determines the desired value of quantity being controlled.

58) What is Shear Beam ?

ANS: A bending beam load cell in which the strain gauges are mounted on a thin web of material in a machined out cavity in the load cell.

59) What is SIP (Signal in Line Package ) ?

ANS: A flat , molded component package having terminals along one side.

60) What is span ?

ANS: The difference between the highest and lowest value .

61) What are standard test conditions ?

ans: The different environmental conditions under which measurements should be made . For e.g. Temperature and Barometric Pressure.

62) What is Strain Gauge ?

ans: A for detecting the strain that certain force produces on a body .

63) What is Tare Weight ?

ans: A weight of empty container or vehicle .

64) What is temperature coefficient ?

ans: A quantity which drifts (changes) under influence of temperature.

65) What is terminal resistance ?

ANS: A resistance of  load cell circuit measured at specific terminals at standard temperature with no load applied with excitation & output terminals open circuited.

66) What is tolerance ?

ANS: The amount of error that is allowed in a value. It is usually expressed as percent of nominal value, plus or minus units of measurement .

67) What is traceability ?

ANS: The step by step transfer process by which the load cell calibration can be related to primary standards.

68) What is transducer ?

ANS: A device that converts energy from one form to other.

69) What is Trim ?

ANS: To make fine adjustment as of load cell outputs in multi cell systems.

70) What is minimum verification scale division/load cell ?

ANS: A parameter used to select load cell for approved applications.

71) What is weight ?

ANS: The force or amount of gravitational force by which an object is attracted towards center of earth .

72) What is zero balance ?

ANS: The output signal of load cell with rated excitation and with no load applied .

73) What is zero stability ?

ANS: The degree to which the load cell maintains the zero balance with all environmental conditions and other variable remaining constant .

74) What is weighing ?

ANS: Measurement of Mass is known as weighing & measurement of gravitational force is known as Weight of Commodity.

75) What are weighing units ?

ANS: Weight is measured worldwide with MKS system. Those units in MKS are milligrams , grams , kilograms etc.

76) What are methods of Weighing ?

ANS: Weighing is either Mechanical or Analogue weighing and Electronic weighing.

77) What is Mechanical or Analogue Weighing ?

ANS: To create balance on horizontal surface & balance from middle point to get measurement of  any commodity .In counter weight method, there is one fine calibrated bar to weight massive commodities more than 100 kgs. These type of scales are known as platform scales. This is also known as Lever method of weighing.

78) What are Electronic weighing scales ?

ANS: This method of weighing uses sensors instead of levers for  weights. It senses the weight and get output in mill volts. The weighing sensor is known as Load Cell. Analogue to Digital converter (A/D ) used for conversion from mechanical signal to electrical signal .

79) What are different categories of weighing scales ?

ANS:

1) Micro Scales : To weigh high value commodities. It includes Laboratory Precision Scales, Gems and Jewellary Scales , Pocket Scales and high accuracy scales.

2) Table-top and Counter Scales : These are popular and highest use weighing machines and as per name used in small and medium scale trades like Grocery , Dairy , Grain Merchant , Provisions(Retails and Super-Stores) and Price Computing Scales .

3) Platform Scales : These are high capacity scales with least count. These
are Desk-top scales, Common Platform ,Industrial Platform and Heavy Duty Scales .

4) Crane Scales : Commodities with very high capacity which are not possible to handle by hand are lifted and weighted through crane scales.

5)Truck Scales/Weighbridges : These are vehicle loading scales and of type Pit , Pitless , Weigh-In-Motion and Axle Pads.

6)Special Application Scales : These are used in Batching , Belt weighing , Check weighing and Packing Systems .

80)  What are indicators ?

ANS: This is a unit which consists of power supply , process unit & display .

81) What is display ?

ANS: It gives you indication for weight , price , commodity etc. There are different displays available as

82) What is Pan and Platform ?

ANS: Pan is used as base for small capacity weighing while Platform is used for large capacity weighing base. Size of Pan or Platform is measured in mm.