This unit involves the skills and knowledge required to develop, enter and verify programs for programmable logic controller (PLC) (also known as programmable controller) for a system requiring discrete control functions.

It includes working safely, using control systems and control system development methods, using ladder diagrams/statement list/function block diagram instruction sets, following written instructions, and documenting program development and testing activities.

No licensing, legislative or certification requirements apply to this unit at the time of publication.

ELEMENTS

PERFORMANCE CRITERIA

Elements describe the essential outcomes.

Performance criteria describe the performance needed to demonstrate achievement of the element.

1

Identify control system requirements

1.1

PLC operating functions, parameters and specifications are determined from relevant documentation, electrical drawings or persons to determine the control system scope of work

1.2

Work health and safety (WHS)/occupational health and safety (OHS) requirements and workplace procedures for a given work area are identified and applied

1.3

Control system scenario is developed from job specifications of process/plant/machine controlled through consultation with relevant person/s

1.4

PLC block diagram is developed using industry standard symbols

1.5

Infotechnology equipment, software and measuring devices needed to carry out the PLC work are obtained and checked for correct operation and safety

1.6

Installation of PLC is checked for compliance with relevant industry standards, regulations and job specifications

2

Develop control system, enter and test program

2.1

Established WHS/OHS risk control measures and procedures for carrying out the work are followed.

2.2

Circuits/machines/plant are checked and isolated in accordance with workplace procedures

2.3

Control system solutions are developed and documented based on specified control mode and using acceptable methods for designing control systems

2.4

Developed control system is converted to an appropriate form

2.5

Program is entered into the PLC using appropriate infotechnology and software

2.6

Entered instructions and settings are tested in accordance with job specifications by control system scenario

2.7

Appropriate methods and tools are used to test control system and operating faults and anomalies are identified and rectified

2.8

Unplanned situations are responded to in accordance with workplace procedures, in a manner that minimises risk to persons and equipment

3

Verify document and report programming activities

3.1

WHS/OHS work completion risk control measures and procedures are followed

3.2

Program is transferred from PLC to external medium for storage

3.3

Control system specification and program are documented in accordance with workplace procedures

3.4

Work completion is documented and relevant persons notified in accordance with workplace procedures

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions on at least two separate occasions and include:

applying relevant work health and safety (WHS)/occupational health and safety (OHS) requirements, including identifying programmable logic controller (PLC) risk control measures

connecting the PLC

correcting programming anomalies

dealing with unplanned situations in accordance with workplace procedures in a manner that minimises risk to persons and control equipment

developing applications for PLC functions including operation and programming of inputs and outputs

developing a control system solution to specified operating functions and parameters

developing a PLC block diagram, including identifying industry standard PLC symbols

documenting control system and programming

identifying PLC modules and applications

programming a PLC using industry standard methods such as master control, jump, shift register, step sequencing, timers and counters

testing and verify control system inputs and outputs operation

transferring programs to PLC

documenting control system and programming clearly

identifying non-compliance conditions of device installation

converting control system to a PLC program

entering programming functions and parameters correctly

transferring program to external storage.

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions and include knowledge of:

PLC introduction including:

evolution of the programmable controller and applications

relay control, static logic control and programmable control

programmable controller block diagram (inputs and outputs)

programmable controller advantages, symbols and functions

numbering systems start-up procedures

programming inputs and outputs

operation of programmable controller inputs

PLC operation: scan cycle

basic programming

types of PLC programs, including:

ladder diagrams

basic programming

program modification

ladder diagram development

connecting the programmable controller

programming timers, including:

purpose of timers

timer instructions

on-delay and off-delay timer instruction

programming timers

retentive and non-retentive timers

cascading timers

the self-resetting timer

monitoring timers

circuit conversion

programming counters, including:

counter instructions

retentive and non-retentive, up/down, programming, self-resetting and cascading counters

circuit conversion

program storage, including:

PLC terms

memory

the programmable read only memory (PROM) pack

printing ladder diagrams

PLC input and output modules, including:

purpose of modules

analogue, dry contact, alternating current (a.c.) and direct current (d.c.) input modules

relay, triac, transistor and analogue output modules

PLC installation requirements, including:

installation precautions

safety systems

mounting the PLC

installation documentation

routing signal and power cables

earthing requirements

master control, including:

master control relay

master control relay ladder diagram

programming master control relays

jump function, including:

jump function

jump function ladder diagram

programming jump functions

the shift register, including:

purpose of registers

the shift register

shift register operation

clock input

shift register requirements

programming shift registers

the step sequencer, including:

step sequencers

step sequencer operation

clock input

step sequencer requirements

programming step sequencer

PLC diagnostics and fault finding, including:

PLC fault finding

controller status

input/output (I/O) faults

program faults

relevant risk mitigation processes

relevant WHS/OHS legislated requirements

relevant workplace documentation, including relevant industry standard documentation and regulations related to PLCs

relevant workplace policies and procedures.

Assessors must hold credentials specified within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must satisfy the Principles of Assessment and Rules of Evidence and all regulatory requirements included within the Standards for Registered Training Organisations current at the time of assessment.

Assessment must occur in workplace operational situations where it is appropriate to do so; where this is not appropriate, assessment must occur in simulated workplace operational situations that replicate workplace conditions.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

Resources for assessment must include access to:

a range of relevant exercises, case studies and/or other simulations

relevant and appropriate materials, tools, equipment and personal protective equipment (PPE) currently used in industry

applicable documentation, including workplace procedures, equipment specifications, regulations, codes of practice and operation manuals.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.

Range is restricted to essential operating conditions and any other variables essential to the work environment.

Non-essential conditions may be found in the UEE Electrotechnology Training Package Companion Volume Implementation Guide.

Developing, entering and verifying programs for PLCs must include at least five (5) of the following functions/controls:

bit shift registers

cascading counters

cascading timers

combining timers and counters

constant duty cycle

derived timers (off delay)

internal relays/flags/markers

jump instructions

latching relays (set/reset)

master control instructions

one shot

retentive (power fail) functions

reversible counters

scan time considerations

self-resetting

simple step sequence instructions

Electrotechnology

Instrumentation & Control