Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

      A  B  C  D  E  F  G  H  I  J  K  L  M
     N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Index Column

Index

3 Phase Power

7-Segment Code
7-segment display - ladder logic

74XXX TTL Data Sheets

A


abampere

abbreviations:
     Electrical Engineering Abbreviations and Acronyms
     Military Abbreviations and Acronyms

ABCD matrices for transmission lines

Absolute Pressure

Absolute Viscosity

absorption spectra

acids - pH of common inorganic acids

activity series of metals

adder:
     full-adder
     half-adder

air composition

Air Pressure Loss For Every 100 Feet of Clean Commercial Steel Pipe

American National Standard Letter Designation for Welding and Allied Processes (ANSI/AWS A2.4-9I)

American Standard Code for Information Interchange (ASCII)

American Wire Gauge (AWG)

Ampacity of Copper and Aluminum Insulated Wire

ampere

Ampere's Circuital Law

amplifier - General purpose Amplifier

amplifier - general purpose inverting amplifier

angle between two vectors

Angular Speed Formula

Angular Velocity Formula

apparent power

area of two dimensional shapes

area unit conversion calculator

Atmospheric Pressure at Altitudes Above Sea Level

AutoCAD Notes

AutoDesk AutoCAD Notes

automation

AWG (American Wire Gage)



battery technology

beam:
     structural beams

Beam Deflection

Beam Design and Analysis for Moment and Shear

Belt:
     V-belt:
          Commercially available "5V" Sheave Pitch Diameter
          dimensions
          sizing chart
          Belt Reduced Power Capability with Contact Angle

Bernoulli's Law

bevel gear

Blot-Savart Law for Magnetic Field & Lorentz Force Equation

Bleeder Valve

blinking lamp circuit - ladder logic

bolt: Eccentrically Loaded Bolts

bolt and nut materials

bolt technical reference guide

Boltzmann constant

Bonding between atoms and molecules

boolean algebra summary

Boundary Conditions

Boyle's Law

BSPT (British Standard Pipe Thread)

BSPP (British Standard Parallel Pipe)

Bulk Modulus of Common Substances

Buoyancy Force

 

camera: contact lens camera

camera: vision system cameras

Capacitance, Conductance, and Inductance

Capacitor

capacitor energy storage

Cartesian Coordinate System

Cartesian, Cylindrical, Spherical Conversions

centroids of two dimensional shapes

Ceramics

chain pitch selection chart for roller chains

chain sprocket and platewheels

Charge Distributions

charge of an electron

charge of a proton

Charles's Law

Chebyshev Frequency Response for n=4

Check Valve

circle

circuit breaker

circuit components

co-function identities

codes:
     2 out of 5 code
     7-Segment Code
     ASCII
     Gray Codes

Coefficients of Friction

Coefficients of Linear Thermal Expansion

Column Design and Analysis

Combined Stresses, Axial, Bending, Shear: Mohr's Circle

comparator

Comparison of Properties of Straight Tungsten Carbides and Tool Steels

complex trigonometric identities

complex numbers

Complex Numbers and Phasor Techniques

compressor

Compton scattering

connectors

connectors - modular connectors

Connections: Bolted and Welded

contact configurations

contact lens camera

contactor

Continuity Equation in Fluid Mechanics

Continuity Equation in Electromagnetism

conversions (number base):
     binary to decimal conversion
     binary to hexadecimal conversion
     binary to octal conversion
     decimal to binary conversion
     decimal to hexadecimal conversion
     decimal to octal conversion
     hexadecimal to binary conversion
     hexadecimal to decimal conversion
     octal to binary conversion
     octal to decimal conversion

conversions between two-port network parameters

Coordinate Systems in Electromagnetism

copper tubing
     dimensions of type K copper tubing

Coulomb's Law

CREO Parametric

cross product

Crystal structures for common metals at room temperature

curl operator

cylinder (pneumatic or hydraulic)

Cylindrical Coordinate System

Cylindrical, Spherical, Cartesian Conversions


D Latch

Dalton's Law of partial pressure

Darcy's Formula

data sheets

DC and AC Circuits

de Broglie Theorem

decibel dB

Decimal Equivalent Chart

decoder - ladder logic

Deflection in Beams

demultiplexer

density unit conversion calculator

dielectric constants of selected materials

dielectric strengths of selected materials

Dielectrics as related to Displacement Flux Density

differential operators

Differential Unit Vector in Cartesian Coordinate System

Differential Unit Vector in Cylindrical Coordinate System

Differential Unit Vector in Spherical Coordinate System

Dimensions of Steel Pipe

Dimensions of Steel Valve and Steel Fittings

diode

diode - Light Emitting Diode (LED)

diode - Schmitt Trigger

diode: Voltage drop across a diode

Directional Valve

distance between point and line

distance between point and plane

Divergence

divergence operator

Divergence Theorem

double angle formulas

dot product

drill bit size conversions

Ductility of Selected Materials Measured as Percent Elongation

earth

Eccentrically Loaded Bolts

efficiency

elastic modulus for selected materials

elastomer: Hardness Scale comparison table of metals and elastomer

electric charge

electric current

Electric Field Intensity

Electric Stored Energy Density

Electrical Metallic Tubing - EMT Sizes, Weights, and Dimensions

Electromagnetic Spectrum

Elements of the Periodic Table

EMT Conduit Sizes, Weights, and Dimensions

encoder

energy storage in a capacitor

Energy Storage in Electric and Magnetic Fields

energy unit conversion calculator

equation of a plane

equations

Euler identity

even-odd identities

Exclusive OR (XOR) vs Exclusive NOR (XNOR)

expansion for hyperbolic functions

expansion for sine, cosine, tangent, cotangent

fans as applied to electrical enclosures

Faraday's Law

Faraday's Law and Ampere's Circuital Law in differential Form

fastener: Thread Series Designation

fastener technical reference guide

FDA:

21 CFR 211 - CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS

FlexiBowl

flip-flop using Omron KEEP instruction

Flow Curve and Typical Values of Strength Coefficient K and Strain Hardening Exponent n for Selected Materials

Flow of Air Through Schedule 40 Steel Pipe

Flow of Water Through Schedule 40 Steel Pipe

Fluid Sealing Material Compatibility Chart

force unit conversion calculator

fractions to decimal conversion table

Frequency Allocation Chart in the US (pdf)

full-adder - ladder logic

Gauss' Law

Gauss' Law derived from Conservation of Charge and Ampere's Law

GD&T (Geometric Dimensioning and Tolerancing)

gear:
     bevel gear
     Gear Types

General Energy Equation (Fluid Mechanics)

Geneva drive

geometric tolerancing

Geometry

golden ratio

golden rectangle

Gradient in Cartesian, Cylindrical and Spherical Coordinates

gradient operator

Gray Code:
     Gray Codes
     how to generate gray codes

Greek alphabet

grippers

parallel grippers

needle grippers (overview)

H Beams & Wide Flange ASTM-A36/A572

H-Bridge

Hagen Poiseuille Law for Laminar Flow

half angle formulas

half-adder - ladder logic

Hamming Codes

Hand Pump System

Hardness Scale comparison table of metals and elastometers

Hazen-Williams Constants for Various Materials

head, Velocity

hexagon

HMI (Human Machine Interface)

hydraulic Horsepower

hydraulic Radius

hydraulic schematic symbols

hyperbolic functions

I Beams ASTM-A36/A572

identities:
     co-function identities
     complex trigonometric identities
     euler identity
     even-odd identities
     Pythagorean identities
     quotient identities
     reciprocal identities
     trigonometric identities
     vector identities

image parameters for T and pi networks

inductor

Inequalities

Infrared Spectrum

insulation: Relationship between an Insulator's K-factor, C-factor, and R-factor

integral tables

intensity of a sound wave

interlock circuit in Ladder Logic

Internal Fluid Pressure (psi) on Tubing

inverter

JK Flip Flop

Junior Beams ASTM-A36

Jupiter

kinematic equations

Kinematic Viscosity

Kirchhoff's Current Law

Ladder Logic Circuits

laminar flow: Hagen Poiseuille Law for Laminar Flow

Laplace Transforms

Laplace's Equation

Laplacian operators

Laplacian of a Scalar Function and a Vector

Latches

Law of Conservation of Charge

Law of cosines

length unit conversion calculator

Lens Types

Lenz's Law

Light Emitting Diode (LED)

Limits - Calculus

List of Natural Elements of the Periodic Table

logarithmic constant

logic functions - ladder logic

logic gates

Lorentz Force Equation

low-pass RC filter

Magnetic Field--Ampere's Law, Biot-Savart Law

Magnetic Field Intensity

Magnetic Flux Density

magnetic force on a moving charge

Magnetic Stored Energy Density

Magnetic Vector Potential

mass/weight unit conversion calculator

mathematical symbols

matrices

Maxwell's equations

mechanical power

Mechanics

mechanisms

Melting Points for Some Common Metals and Alloys

mesh sizes: Strainer Mesh Sizes and Size of Solids Removed When Strainer is Clean

Metals

metals: Hardness Scale comparison table of metals and elastometers

Mesh Size Chart

Microwave Oven (pdf)

millimeters to decimal conversion table

modular connectors

Modulus of elasticity for selected materials

modulus of rigidity

moment of inertia

moment of inertia transfer formula

momentum

Moody Friction Factor Chart

MOSFET:
     N-Channel MOSFET

Motion Control Using Servo and Stepper Motors

Motorola microcontrollers

motors:
     electric motor family tree
     classification of Motors by application
     NEMA classification of Motors
     PWM - pulse width modulation
     Sizing a Motor for Hydraulic Pump
     Standard Electric Motor Sizes
     DC Motor - Compound Wound

multiplexer

Multiplication Table (1 thru 12)

 

NAND (Diode-Transistor Logic)

needle grippers (overview)

NEMA Enclosure Ratings

NEMA Motor Frame Sizes

Neutralization Number

Newton's laws of motion

network functions: Types of Network Functions

NOR (Diode-Transistor Logic)

NPN Transistor

NPT (National Pipe Thread)

NPS (Nominal Pipe Size) - Straight pipe sizes

nut:
     bolt and nut materials

Ohm's Law

OSHA - Safeguarding Equipment and Protecting Employees from Amputations

PanelView: How to connect to PC

parameters:
     image parameters for T and pi networks

Pascal's Law

Permeability of a vacuum (or free space)

pi networks: image parameters for T and pi networks

pipe: dimensions and properties of schedule 40 and 80

Pipe Fitting Dimensions

pipe thread types

periodic table: List of Natural Elements of the Periodic Table

PLA

Plank's Law

plastics

PLC (Programmable Logic Controller)

PNP transistor

Poisson's Equation

Poisson's ratio

polar moment of inertia

Polarization

polygon

polymers

Potential Function for Static and Non Static Fields

power consumed by a resistor

Power developed by the product of the force and velocity

power definition

power - Mechanical Power

power-reducing/half angle formulas

power series representation

power:
     electrical apparent power

power transmitted by a shaft given a torque and speed of a shaft

power unit conversion calculator

powers of two

pressure (psi) conversion factors

Principle of Reciprocity

pressure: Atmospheric Pressure at Altitudes Above Sea Level

pressure: Internal Fluid Pressure (psi) on Tubing

product-to-sum formulas

proximity sensor - inductive

PTC CREO Parametric Notes

pump system: Hand Pump System

PWM (pulse width modulation)

Pythagoras' Theorem

Pythagorean identities

Pythagorean Triples

 

quadratic formula and proof

quotient identities

radius of gyration

range equation

radian measure

RC Time Delay

reciprocal identities

regeneration circuit

Relationship between Shear stress and Tensile stress

relay

relief valve

resistivity

Reynold's Equation

robots - Types of Industrial Robots

Rockwell Hardness Scales

ROM (Read Only Memory)

rubbers

safety - machine safety

safety - standards for machine safety

Sanitary Fittings - Tri-Clamp

Saybolt Universal Viscosity

scalar product of two vectors

Schedule 40 pipe: Working Pressure In PSI (psi) in Standard Pipe, Extra Heavy Pipe, Double Extra Heavy Pipe

Schmitt Trigger Diode

Schrödinger's equation

Scissor Lift Mechanism

screw materials

screw tapping and clearance chart

screw thread pitch

screw thread series designations

screw thread types

seals: Fluid Sealing Material Compatibility Chart

sensors

seal in contact in Ladder Logic

Shear and Moment Diagrams by the Summation of Areas

shear strain

Shear Strength of Materials

shear stress analysis on a bolt in single shear

shear stress: Relationship between Shear stress and Tensile stress

sheetmetal gauge sizes and weight/ft^2

SI prefixes

Sieve Opening Size Chart

Sizing a Motor Horsepower (HP) for Drilling, Tapping, and Threading

Sizing a Motor horsepower (HP) for Hydraulic Pumps

Sizing a motors horsepower (Hp) and torque for turning a solid round disk

Skin Depth of Copper

Slider-Crank connecting rod angular speed and acceleration

software notes

solar system

spacecrafts

spark plug

Specific Gravity

specific gravity of gases

specific gravity of liquids

Specific Roughness and Hazen-Williams Constants for Various Materials

Specific Weight

Spectrum: Electromagnetic Spectrum

Spectrum: Infrared Spectrum

speed of sound

speed unit conversion calculator

Spherical Coordinate System

Spherical, Cylindrical, Cartesian Conversions

sprockets and platewheel types

SR Latch

SR Master-Slave Flip-Flop

Stainless Steel Chemical Composition

Standard Electric Motor Sizes

standards for machine safety

Stefan-Boltzmann Law

Stepper Motor Wiring Diagrams

Stokes' Theorem

straight pipe sizes - NPS

strain hardening exponent: Flow Curve and Typical Values of Strength Coefficient K and Strain Hardening Exponent n for Selected Materials

Strainer Mesh Sizes and Size of Solids Removed When Strainer is Clean

strength coefficient: Flow Curve and Typical Values of Strength Coefficient K and Strain Hardening Exponent n for Selected Materials

Strength of Materials

Stress-Strain Curves (pdf)

Stress Summary

Stresses in Beams and Built up Sections and Bolt Spacing

Structural Members

summing junction amplifier

sum or difference of two angles

sum-to-product formulas

sun

sun spot

symbols - electrical symbols

symbols - mathematical symbols

synchronous belt

T networks:
     image parameters for T and pi networks

Tangent Line Problem

tap drill reference

temperature unit conversion calculator

tensile strength: Yield Strength and Tensile Strength for Selected Metals

thermal conductivities of various media

thermal expansion

thermal expansion: Coefficients of Linear Thermal Expansion

Thread Series Designations

thread types - screw

thread types: pipe thread types

time delay - RC Time Delay

timing belt

toggle output with a single pushbutton - ladder logic

toggle output using single pushbutton with different TON and TOFF delays - Ladder Logic

Tonnage for Hole Punching

tool steel:
     Comparison of Properties of Straight Tungsten Carbides and Tool Steels

tool steels

Torricelli's Theorem

Torque Couplings

torque unit conversion calculator

torsion

torsional deflection of a shaft

transformer

transistor - NPN

transistor - PNP

Transmission Line - Parallel Plate

transmission line table of equations(pdf)

Transmission Line Terminated by Resistive Load

Transmission Line with Discontinuity

Tri-Clamp Sanitary Fittings

triangle

trigonometric functions

trigonometric identities

trigonometric values for common angles

Triple Scalar Product

tubing: Dimensions of Type K Copper Tubing

tungsten carbide:
     Comparison of Properties of Straight Tungsten Carbides and Tool Steels

Two-Phase Alternating Current

Two-Port Network Conversions

Types of Network Functions

unit circle

Unit Vectors: Cylindrical & Cartesian, Spherical & Cartesian

USB - Universal Serial Bus

V-belt: Commercially available "5V" Sheave Pitch Diameter V-Belts

V-belt dimensions

V-belt sizing chart

V-Belt Reduced Power Capability with Contact Angle

valve: Bleeder Valve
valve: Check Valve
valve: Directional Valve
valve: Relief Valve

vector:
     angle between two vectors
     vector cross product
     scalar product of two vectors
     vector identities

viscosity

viscosity Index

vision cameras

vision systems

voltage

voltage - worldwide voltages

voltage divider

Voltage drop across a diode

voltage follower

voltage peak detector

voltage regulator

volume unit conversion calculator

wedge physics

weight/mass unit conversion calculator

Welding Filler Metals For Various Aluminum Alloys

welding processes

welding symbol: Location of Elements of a Welding Symbol

Wide Flange & H Beams ASTM-A36/A572

Wien's Law

Wire:
     American Wire Gauge (AWG)
     Ampacity of Copper and Aluminum Insulated Wire

Working Pressure In PSI (psi) in Standard Pipe, Extra Heavy Pipe, Double Extra Heavy Pipe

worldwide voltages

Exclusive OR (XOR) vs Exclusive NOR (XNOR)

Yield Strength and Tensile Strength for Selected Metals

Young's modulus of elasticity


 
 
 

Five Rung

 

Five Rung

Perhaps the most controversial Ladder Logic Programming Pattern is the Five Rung Logic block. The purpose of the pattern is to encapsulate all the elements required for a single machine “motion”. The idea of what constitutes a motion is a little vague, but it’s generally the following:

  • The PLC does something to initiate a motion (like turn on a valve or tell a robot to move)
  • There is some kind of signal to indicate the motion is complete (such as a sensor)
  • We want to monitor the time it takes to complete and generate a fault if it takes too long

As you can imagine, a lot of machine control can make use of this pattern. Any time you have an air cylinder with feedback sensors (extended/retracted) then you can throw two five-rung logic blocks in there. You can also use it when you have to command a motion controller or a robot to move one or more axes to a given position.

The Five Rung pattern is called that because there are 5 coils typically used:

  • Precondition (aka Trigger)
  • Safety
  • Command
  • Complete (aka “In Position”)
  • Fault

Five Rung

Some variants of this pattern would put the Safety rung before the Trigger rung, but I like to reverse that because the Trigger rung really indicates when the motion starts. In a typical program, if you’re using the Step pattern, then the trigger will be driven by a Step In Progress contact. Note that in a more complicated program this motion might be initiated by many different steps in your sequence, so you just put a bunch of Step In Progress contacts in parallel here. In a program that doesn’t use the Step pattern, then the Trigger coil could be driven directly by logic like some other cylinder extended and a part present input on. It’s important to realize that the Step pattern is more scalable and better for larger programs, but it’s not the only way to do it.

The Trigger coil only has to be on to initiate motion and only works if the machine is in Auto Mode. The Trigger coil doesn’t have to stay on the whole time. In some cases it might be common to put the motion complete sensor in this rung as a normally closed contact, so that the motion won’t initiate if the axis is already in that position. That’s redundant in our case because we take care of that later, as you’ll see.

The Safety rung is a set of conditions that have to be true during the entire motion. The prototypical example is “all E-Stops OK” but other conditions you would see here are signals from interfering axes. For example, let’s say that you have two cylinders, A and B, and only one of those can be extended at a time. It’s typical to put the Cylinder A Retracted sensor (and the Cylinder A Extend output) in the Safety rung for the Cylinder B Extend Five-Rung block, and vice-versa. This is a good double-check of your logic, so even if you make a mistake in your sequence logic, at least you’ll prevent the two cylinders from crashing into each other.

The Command rung acts as the memory in this pattern. It remembers that we’re trying to perform this motion. It can be initiated in Auto Mode by the Trigger signal or in Manual Mode by a button or other manual control. Note that the Safety conditions still have to be met even in Manual Mode, so we don’t risk allowing the operator to crash the machine inadvertently. Once the Command coil turns on, it seals itself in, typically until the motion is complete, but alternatively the circuit will be broken if the Safety rung drops out, which is basically an Abort.

Note that the example above shows an “Auto Mode” signal but you will typically see this replaced with an Auto Cycle Running signal, since most machines require you to put the machine into Auto Mode and then initiate a cycle with another button. Sometimes this is captured in the Command rung, and sometimes this is done in the Trigger rung.

The In Position rung is responsible for figuring out how you know that the motion is complete. If you have a sensor, you can use that. If you have a Motion Complete signal coming back from a motion controller or a robot, you can easily use a rising edge detection on that signal as well (in this case I would call this a Complete rung, not an In Position rung). It may also be common to put a timer in this rung to “make sure” that the motion really is complete before we do whatever is next. I prefer not to use timers unless I have some kind of nuisance problem with the machine, but I’ve seen some logic where there’s a timer in every single In Position rung. The problem with timers is that they slow down your cycle time, and nobody wants that. Note that it’s a good idea to use the In Position coil as the canonical indication that this axis is in this position. By that I mean if other parts of your program need to know that your cylinder is in the Extended position, it’s better to use this In Position coil rather than using the inputs themselves. That gives you a single place to change your logic if, for instance, you have to move the sensor to another input due to a blown input, or you want to add a timer due to “bouncing”. If you’re using the Step pattern, it’s typical to use the In Position signal in your Step Complete rung.

The next two rungs, together, make up the Fault rung and you may sometimes see them combined into a single rung depending on the programmer’s preference. The Fault rung implements a simple Timeout Fault for the motion. If you’re trying to extend a cylinder, and it takes more than a second, chances are there’s a problem. This is an example of the State Coil pattern, and requires the operator to reset the fault to continue. It’s important that this fault be reported to the operator to indicate which motion was causing the problem. Note that it also drops out the Safety rung to abort the motion. This is optional, but generally a good idea because it’s possible that the axis or cylinder is jammed and you want to stop trying to move it to prevent further damage to the machine. It isn’t always the case that you want to stop the motion, so use your judgement.

In my programs I’ll typically use a three level system of ladder logic patterns:

  • Highest level: the Mission pattern
  • Middle level: the Step pattern
  • Lowest level: the Five Rung pattern

For example, a Mission might be “Pick Up Part”. Then there will be a routine with all the Steps necessary to perform a pick-up-part sequence, such as “Extend Arm and Turn on Vacuum”, “Extend Gripper”, “Verify Suction”, “Retract Gripper”, “Retract Arm”. Then I would have several low-level routines, such as “Arm”, “Gripper”, and “Vacuum”. The Arm and Gripper routines would each have two Five Rung logic blocks in them, one for Extend and one for Retract. The Vacuum isn’t really a motion, so it would have simpler on/off type logic, and some kind of vacuum sensor feedback logic in it.

I should warn you that when someone first sees a Five Rung logic block, they usually ask, “why do you need so much logic just to turn a valve on?” Well, that’s the difference between an experienced ladder logic programmer and an inexperienced one. Eventually the inexperienced programmer will write some really simple and straightforward logic to turn the valve on and off, and then they’ll have to add some kind of fault when the cylinder motion doesn’t complete (or the sensor stops working), and then they’ll have to differentiate between how it operates in Manual Mode instead of Automatic Mode, and before they know it they’ll have created their own custom version of a Five Rung logic block. In their next program they’ll probably just do it this way.

 

 

©2024 tigerquesttech.com