Maintaining process controller equipment within an engineered system
Overview
This standard identifies the competences you need to carry out corrective maintenance to process controller equipment within an engineered system, in accordance with approved procedures. You will be required to maintain a range of process controller equipment, that typically includes process controllers or sequential controllers (such as programmable logic controllers (PLCs), robots) which are working in an integrated system involving two of the following interactive technologies: mechanical, electrical or fluid power.
This will involve dismantling, removing and replacing faulty peripheral components, process controller units, and components, down to board level on unitary' orrack' type process controller systems. You will also need to be able to load and download process controller programs, check them for errors, make alterations to programs, and create and maintain back-up copies of completed programs.
Your responsibilities will require you to comply with organisational policy and procedures for the maintenance activities undertaken, and to report any problems with the maintenance activities, process control system, tools or equipment used that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. You will be expected to work with minimal supervision, taking personal responsibility for your actions, and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work, and will provide an informed approach to applying maintenance procedures on process controller systems within an integrated system. You will understand the maintenance methods and procedures used, and their application, and will know about the various process controller units and peripheral components, their functions and associated defects, in adequate depth to provide a sound basis for carrying out the maintenance activities, correcting faults and ensuring that the equipment operates to the required specification and remains compliant with all standards and regulations. You will also know about the interaction of the other associated integrated technologies and have sufficient knowledge to carry out the dismantling and reassembly of the process controller system safely and effectively.
You will understand the safety precautions required when carrying out the maintenance activities, especially those for isolating the equipment and for taking the necessary safeguards to protect yourself and others in the workplace. You will be required to demonstrate safe working practices throughout.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety legislation and other relevant regulations, directives and guidelines
- follow the relevant maintenance schedules to carry out the required work
- carry out the maintenance activities within the limits of your personal authority
- carry out the maintenance activities in the specified sequence and in an agreed timescale
- report any instances where the maintenance activities cannot be fully met or where there are identified defects outside the planned schedule
- complete and store all relevant maintenance documentation in accordance with organisational requirements
- dispose of waste materials in accordance with safe working practices and approved procedures and leave the work area in a safe condition
Knowledge and Understanding
You need to know and understand:
- the health and safety requirements of the area in which the maintenance activity is to take place, and the responsibility these requirements place on you
- the isolation and lock-off procedure or permit-to-work procedure that applies to the system being worked on
- the isolation procedure which is specific to the process controller system being worked on
- the specific health and safety precautions that need to be applied during the maintenance activities, and their effects on others
- what constitutes a hazardous voltage and how to recognise victims of electric shock
- how to reduce the risks of a phase to earth shock (such as insulated tools, rubber matting and isolating transformers)
- the importance of wearing protective clothing and other appropriate safety equipment (PPE) during the maintenance activities, and where this can be obtained
- the procedures and precautions to be adopted to eliminate electrostatic discharge (ESD) hazards
- hazards associated with carrying out maintenance activities on a process controlled integrated system (such as handling fluids, stored pressure/force, electrical supplies, process controller interface, using damaged or badly maintained tools and equipment, not following laid-down maintenance procedures), and how to minimise these and reduce any risks
- how to obtain and interpret drawings, charts, specifications, manufacturers' manuals, history/maintenance reports, symbols used on process controller documents, and other documents needed for the maintenance activities
- the basic principles of how the system functions, its operation sequence, the working purpose of individual units/components, and how they interact
- the devices and systems for storing programmes
- procedures to be applied to storage, location and method of backing up programmes
- the different types of interface cards, and their application
- the procedures for the application of computer-based authoring software for design and development
- the numbering system and codes used for identification inputs and outputs
- how to search a programme within the process controller for specific elements
- programming techniques and codes used (such as interlocking, timers, counters, sub-routines)
- the techniques involved in editing, entering and removing contacts from lines of logic and, where applicable, the procedure to be followed for
on' andoff-line' programming - the procedure for obtaining replacement parts, materials and other consumables necessary for the maintenance process
- organisational policy on repair/replacement of components during the maintenance activities
- the techniques used to dismantle/assemble integrated equipment (such as release of pressures/force, proofmarking to aid re-assembly, plugging exposed pipe/component openings, dealing with soldered joints, screwed, clamped and crimped connections)
- methods of attaching identification marks/labels to removed components or cables to assist with re-assembly
- methods of checking that components are fit for purpose, and the need to replace items such as batteries, boards and other failed items
- how to check that tools and equipment are free from damage or defects, are in a safe and usable condition, and are configured correctly for the intended purpose
- the importance of making `off-load' checks before proving the equipment with the electrical supply on
- the generation of maintenance documentation and/or reports on completion of the maintenance activity
- the equipment operating and control procedures to be applied during the maintenance activity
- how to use lifting and handling equipment in the maintenance activity
- the problems that can occur during the maintenance of the process controller system, and how they can be overcome
the organisational procedure to be adopted for the safe disposal of waste of all types of materials
the extent of your own authority and to whom you should report if you have a problem you cannot resolve
Scope/range
Carry out all of the following during the maintenance activities:
- plan and communicate the maintenance activities to cause minimal disruption to normal working
- obtain and use the correct issue of organisational and/or manufacturers' drawings and maintenance documentation
- adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure the safe isolation of equipment (such as mechanical, electricity, gas, air or fluids)
- provide and maintain safe access and working arrangements for the maintenance area
- carry out the maintenance activities using appropriate techniques and procedures
- reconnect and return the system to service on completion of the maintenance activities
- record the results of the maintenance activity and report any defects found
- dispose of waste materials in accordance with safe working practices and approved proceduresand leave the work area in a safe condition
Use appropriate dismantling and re-assembly techniques to deal with two of the following:
mechanical components:
1. draining and replenishing of fluids / release of gas pressure and safe isolation
2. removing and refitting locking and retaining devices
3. removing minor mechanical units/sub-assemblies (such as guards, structures)
4. removing major mechanical units (such as gear boxes, pumps, mechanical handling, workholding/transfer equipment)
5. proofmarking components to aid reassembly
6. setting, aligning and adjusting replaced units
electrical components
7. isolating the power supply using correct lock-off communication procedure
8. disconnecting and re-connecting wires/cables
9. removing and replacing major electrical components (such as motors, switch/control gear)
10. removing and replacing minor electrical components (such as relays, sensing devices, limit switches)
11. removing and replacing wiring enclosures (such as conduit, trunking and cable traywork)
fluid power components
12. releasing stored pressure
13. chocking/supporting cylinders/rams/components
14. disconnecting/removing hoses / pipes
15. removing and replacing units/components (such as pumps, valves, actuators)
Carry out maintenance activities on one of the following types of process controller equipment:
- fixed inputs/outputs (I/O)
- modular
- rack mount
Carry out seven of the following program maintenance activities on the process controller system:
- select and use appropriate programming devices (such as terminals, handheld programmers and personal computers)
- use ladder logic, statement lists, or system flowcharts
- force contacts on and off
- edit, enter and remove contacts from lines of logic
- alter counter and timer settings
- use
on' andoff-line' programming - carry out on-line monitoring of programs
- load, read and save programs
- produce back-ups of completed programs
- programme by computer based authoring (to include sub-routines)
- use single-step mode of operation
Carry out all of the following during the maintenance activities:
- take electrostatic discharge (ESD) precautions when working on or close to sensitive components and circuit boards
- proofmark or label removed wires and components
- inspect and/or test components for serviceability
- use program full-run modes of operation
- change or add circuit boards
- replace power supplies
- replace peripherals (such as sensors, actuators, relays, switches)
- replace process controller units
- replace back-up batteries
- functionally test the system
Ensure maintenance activities comply with one of the following:
- organisational guidelines and codes of practice
- BS, ISO and/or BSEN standards
- equipment manufacturer's operation range
Complete and store all relevant maintenance documentation in accordance with organisational requirements, using one of the following:
- job cards
- maintenance log or report
- permits to work/formal risk assessment and/or sign on/off procedures
- organisational-specific documentation
- electronic reports