Meisterprüfung Mechatronik flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Mechatronic system

An integrated system combining mechanical, electrical/electronic, control, and software subsystems designed together to achieve a function that no single discipline could deliver alone.

Sensor sensitivity

The ratio of output signal change to input quantity change; a higher sensitivity gives a larger output for the same measured change but does not necessarily improve accuracy.

Stepper motor step angle

The angular displacement per full step, equal to 360 degrees divided by the number of steps per revolution; microstepping subdivides this angle electronically.

Inertia ratio

The ratio of load inertia reflected to the motor shaft divided by motor rotor inertia; low ratios improve dynamic response and stability in servo systems.

Ohm's law

The relationship U = R times I for a resistive element, where U is voltage in volts, R is resistance in ohms, and I is current in amperes.

Three-phase power

Total active power in a balanced three-phase system equals the square root of three times line voltage times line current times the power factor cosine phi.

Resonant frequency RLC

The frequency at which inductive and capacitive reactances cancel, f = 1 divided by 2 pi times the square root of L times C; impedance is then purely resistive.

RCD residual current device

A protective device that compares currents in live and neutral conductors and trips when the residual current exceeds its rated value, typically 30 milliamperes for socket circuits.

Hooke's law

In the elastic range, stress is proportional to strain: sigma equals E times epsilon, where E is the modulus of elasticity of the material.

Bending stress

The maximum normal stress in a bent beam equals the bending moment divided by the section modulus W; for a rectangular section W equals b times h squared divided by six.

Bearing rating life

The basic rating life L10 is the number of revolutions reached by 90 percent of a group of identical bearings, calculated as (C/P) raised to p times one million.

ISO fit system

A standardized system of tolerances and fits using hole basis H and shaft basis h, with clearance, transition, and interference fits defined by tolerance grades IT01 to IT18.

PID controller equation

The controller output equals Kp times the error plus Ki times the integral of error plus Kd times the derivative of error, combining proportional, integral, and derivative actions.

Ziegler-Nichols tuning

A tuning method using the ultimate gain Ku and oscillation period Tu; for PID set Kp to 0.6 Ku, integral time to 0.5 Tu, and derivative time to 0.125 Tu.

Damping ratio

A dimensionless parameter describing how oscillations decay in a second-order system; values below one produce overshoot, one is critically damped, above one is overdamped.

PLC scan cycle

The cyclic sequence of reading inputs, executing the control program, and writing outputs; the scan time must be shorter than the fastest process reaction time.

MTBF

Mean time between failures, calculated as total operating time divided by the number of failures; the reciprocal is the failure rate used in reliability calculations.

Availability

The proportion of time a system is operational, calculated as MTBF divided by the sum of MTBF and MTTR; higher repair speed increases availability.

Vibration unbalance signature

A rotating unbalance produces a dominant vibration component at one times the rotational frequency, distinguishing it from misalignment which shows a strong two-times component.

Insulation resistance test

A DC voltage test, typically 500 volts, measuring resistance between live conductors and protective earth; values below one megohm for 230/400 volt circuits indicate a fault.

Geometric tolerancing symbols

ISO 1101 symbols specify form, orientation, location, and run-out tolerances in a feature control frame, ensuring interchangeability beyond simple dimensional tolerances.

Surface roughness Ra

The arithmetic mean deviation of the assessed profile from its mean line, expressed in micrometres and specified on drawings per ISO 1302.

Circuit diagram reference designators

Standardized alphanumeric labels such as K1 for relays, M1 for motors, and Q1 for protective devices, used with cross-references to link contacts and coils across sheets.

Machinery Directive 2006/42/EC

The European directive requiring manufacturers to perform risk assessment, apply harmonized standards, compile a technical file, issue a Declaration of Conformity, and affix the CE mark.

Performance Level PL

A safety-related reliability classification from EN ISO 13849-1, ranging from a to e, determined by category, mean time to dangerous failure, and diagnostic coverage.

Five safety rules

For work on electrical installations: disconnect, secure against reconnection, verify absence of voltage, earth and short-circuit, and cover adjacent live parts.

Break-even quantity

The production volume at which total revenue equals total cost, calculated as fixed costs divided by the difference between unit price and unit variable cost.

Net present value

The sum of discounted future cash flows minus the initial investment; a positive NPV indicates the investment earns more than the required rate of return.

OEE

Overall equipment effectiveness, the product of availability, performance rate, and quality rate; it measures how effectively a machine is utilized.

Dual vocational system

The German training model in which apprentices learn at a company under an Ausbildungsrahmenplan and at a vocational school following a Rahmenlehrplan, coordinated by the chamber.

Ausbildungsnachweis

The training record book in which apprentices document their activities; it must be kept regularly and reviewed by the trainer, and is required for final examination admission.

ISO 9001 process approach

A quality management principle that treats activities as interrelated processes, applying risk-based thinking and the plan-do-check-act cycle to achieve consistent customer satisfaction.