ANEXOS
A.10. Desarrollo de procesos de fabricación
Crane motions may be controlled by one or a combination of the following, or other, appropriate methods:
(a) Manual controls, i.e. human operator:
(i) Cabin controls (see Clause 8.7.3.1).
(ii) Pendent control station (see Clause 8.7.3.2).
(iii) Whole-current controller (see Clause 8.7.3.3).
(iv) Master controller or combination controller.
(v) Cordless controls including radio control, microwave control and infra-red control (see Clause 8.7.3.4).
(b) Automatic control, i.e. no human operator (see Clause 8.7.5).
(c) Semi-automatic, i.e. combination of Items (a) and (b).
8.7.2 Requirements common to all controllers
All controllers and the equipment associated with them shall comply with the following requirements:
(a) The control system and equipment shall provide fail-safe operation at all times including during times when there has been a failure of the power supply, the system or any component thereof.
(b) All types of manual controls such as pushbuttons, switches, joysticks, levers and pedals which control motion shall be of the hold-to-run type and shall be positive in operation, returning to the neutral position upon release.
(c) Wiring and equipment shall be of appropriate types and located and enclosed with materials and in a manner appropriate to the most severe environment in which the crane is to operate.
(d) Wiring shall not carry loads of a physical nature under any of the conditions under which the crane is to operate. Pendent wire and flexible cables shall be supported to ensure compliance with this Clause (see also Clause 8.14.6).
(e) Where a crane can be controlled by more than one controller or control system, provision shall be made to ensure that only one system can control the crane at any one time.
(f) Controllers including pushbuttons, switches, and the like, shall be of such shape and arrangement as will enable ready and convenient operation of each such item and obviate inadvertent operation of, or damage to, the item.
Where a controller or pushbutton provides stepped speed control, physical movement of the controller shall be in easily distinguishable positive steps.
(g) An emergency stop control shall be provided at each control station. Operation of the emergency stop control shall immediately cause all crane motions to cease.
Emergency stops shall be of the positive break type and require manual reset.
(h) Cranes fitted with multiple hoists, which can be operated in combination, shall indicate to the operator which hoist is selected. Where indicating lights are provided, a test facility at the operator controls shall be provided to test the condition of the indicators.
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8.7.3 Manual control
8.7.3.1 Cabin control stations
The requirements for the cabin are detailed in Clause 11.2. The requirements for the controllers installed within the cabin or adjacent to it or both as applicable are set out in the relevant parts of this Clause.
8.7.3.2 Pendent control station 8.7.3.2.1 Electrical power supply
The nominal working voltage shall not exceed 50 V a.c. or 120 V d.c. except where both of the following conditions apply, in which case a low voltage up to 440 V a.c. may be used:
(a) A controller not subject to conditions of external weather, wet or damp situations, condensation or any other adverse conditions;
(b) Pendent control stations that are double-insulated in accordance with AS/NZS 3100.
Transformers that supply pendent control stations shall comply with Clause 8.9.
The electric cable to each pendent control station shall be double-insulated and flexible and shall be securely attached at both ends so that the cable only carries its own mass. Where appropriate the cable shall comply with Clause 8.14.6.
8.7.3.2.2 Design and construction
Each pendent control station shall have a rating appropriate to the voltage of the electrical power supply to the control station and shall comply with AS/NZS 3100 and with AS/NZS 3947.5.1. The requirements for the materials of the station are covered in Clause 8.7.2. The type of enclosure for each pendent control station shall be appropriate for the conditions to which the control station is subjected and shall be rated not less than IP55 as defined in AS 1939.
8.7.3.2.3 Pendent support cable
The pendent cable supporting a pendent control station (or stations) shall comprise one or more flexible steel wire cores or other suitable material, with the electric cable attached to the support wire. The support cables shall be able to withstand a tensile force of not less than 1 kN.
Where the pendent control station is double-insulated, the support cable shall be effectively insulated from the crane structure.
Where the pendent control station may be used to pull a monorail hoist or crane along its runway, the hoist or crane shall be designed to be pulled by a tensile force of not greater than 1 kN.
8.7.3.2.4 Pendent support cable (see also Clause 11.3)
Where controllers are operated by means of pendent cords, means shall be provided to ensure that the controller returns to the ‘off’ position immediately the pendent is released or in the event of the pendent being detached or broken. Where counterweights are used for this purpose, they shall be supported independently of the pendent cord.
The pendent cord arrangement shall be designed to obviate inadvertent operation of a pendent cord, particularly when the crane is in motion. Each pendent cord shall be marked in accordance with Section 11 to indicate the motion and direction of movement it controls.
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8.7.3.3 Whole-current controller 8.7.3.3.1 Method of operation
Each whole current controller shall be capable of—
(a) interrupting all active conductors, except where otherwise allowed in the appropriate part of AS 1418 or when in the ‘off’ position;
(b) interlocking in the ‘off’ position;
(c) where required, effecting motor reversal after operation of a limit switch (see Clauses 8.8.2 and 8.8.3); and
(d) positive step operation corresponding to the speed steps where the controller provides stepped-speed control.
Whole current controllers shall comply with AS/NZS 3947.5.1.
8.7.3.4 Cordless controllers 8.7.3.4.1 General
Cordless controllers may be used to transmit control signals where the use of hard wiring is not considered suitable or appropriate. Examples of cordless controllers are the following:
(a) Radio-wave signals.
(b) Microwave signals.
(c) Infra-red signals.
NOTES:
1 Under some circumstances, use of these systems requires licensing of the controller.
2 The Australian Communications Authority (ACA) administers a labelling regime for, amongst other things, radiocommunications equipment. Equipment used for remote control purposes will need to comply with any ACA requirements that exist at the time of supply. In addition, the ACA has various licence requirements for radiofrequency devices.
3 IEC 61603-1 provides guidance for the use of infra-red control systems.
8.7.3.4.2 System design requirements
The design and operation of a cordless control system for a crane shall be fail-safe and shall ensure that when the crane is within the range of the control system, power to the motion controllers is possible only when the controller is activated. If the crane is outside the range of the cordless controller, the motions of the crane or monorail shall shut down.
The system shall comply with the following requirements:
(a) With any single fault occurring in the receiver or transmitter, it shall still be possible to render the crane safe by operating the emergency stop or keystop.
(b) Any of the following conditions shall de-energize the main crane contactor:
(i) No valid signal being received for a period exceeding 550 ms.
(ii) Interference from other sources.
(iii) Keystop to ‘off’ position.
(iv) Emergency stop.
(v) No motion being operated for 5 min. This time restraint need not apply if the normal or safe operation of the crane is hindered.
(c) The carrier and address system of each cordless controller shall be positive, fail-safe and tamper-proof and protected as far as possible from spurious signals. When a number of transmitters for different installations are in one building or area, provision
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shall be made to prevent mutual interference. Each cordless control system shall have a unique address code. This shall not preclude the use of specifically designed systems for tandem handover, and multiple transmitter handover.
(d) Interlocking between cordless and electrical controls of the crane shall be arranged so that only one controller method is operative at any one time and the overall fail-safe characteristic of the whole installation is not adversely affected in any manner.
(e) Where a battery is the power source for a transmitter or receiver handpiece or console, the transmitter console or handpiece shall include a low battery warning signal, which may be visual or audible, or both. This signal shall indicate to the operator, at least 5 min prior to the battery output voltage falling below its effective working level, that the radio system is about to shut down, giving the operator sufficient time to take the load to a safe area and set it down and take such other action as is necessary to make the situation safe. Low battery shall not cause any unsafe condition to occur.
(f) The cordless control system shall incorporate sufficient logic such that unless all crane motion actuators are in the off position on start up, there shall be no command output.
(g) The design shall ensure that no function of the system can be activated by any source of interference from sources such as arc welding and direct sunlight.
(h) The emergency stop signal shall be an active monitoring type such that the system response time does not exceed 550 ms.
(i) Where several hoisting machines can be operated by one cordless controller, visual indication shall be provided on each selected hoisting machine indicating it has been selected. A testing facility shall be provided at the cordless controller to test the operation of this indicator.
The console/handpiece shall have a keyswitch capable of being locked in the ‘off’ position to disable the cordless controller.
8.7.4 Electronic control
Each electronic control circuit shall be designed and installed so that it complies with the following requirements:
(a) The system shall be fail-safe.
(b) All mandatory devices and interlocks, safety protection, overload protection, start and stop buttons and final limit switches shall be hard wired, i.e. directly connected, external to the electronic control circuits and shall be positive and fail-safe in operation.
(c) A positive and fail-safe means shall be incorporated in the system of controls to prevent malfunctioning caused by—
(i) the power supply becoming unsuitable for proper operation; and
(ii) incorrect insertion of any plug, or similar component, or absence of any printed circuit board, or the like.
(d) The crane shall not be subject to any movement not dictated by the crane operator due to any fault in the system of controls or any interference. A failure of a discrete or integrated circuit component shall not cause an unsafe condition.
(e) Where provision is made for the equipment to be controlled from a programmable logic controller, computer, or similar device, a positive and fail-safe means shall be provided in the system to ensure that no fault in this type of equipment is capable of
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interfering with the positive isolation of the equipment or result in inadvertent motions when the equipment is in the manual, test, or ‘off’ mode of control.
(f) Where the crane operation has an ‘automatic’ or a ‘semi-automatic’ mode, or both, a function switch shall be provided on the crane operator’s console. The switch shall be positive in operation, and shall be capable of being key-locked in the ‘off’ position only. Provisions shall be made to prevent occurrence of any fault that may cause injury to persons either directly or indirectly, or cause damage within or outside the crane by inadvertent crane motion with the switch in any position.
(g) Where monitoring devices are not duplicated or of a fail-safe type regardless of whether it is a programmable logic controller or any other type, such system shall be monitored with any operation of the controller. Where monitors are duplicated, they shall be checked automatically one against the other, and shall be interlocked with the system of controls in a positive and fail-safe manner.
The system of controls need not be shut down during the automatic checking of the monitoring system, except when the monitor is faulty. On starting of the equipment, overall checking of the safety system of controls shall be done automatically so as to prove its capability of shutting down the equipment.
The operation of the main contactor, directional contactors, and all other contactors, relays, and devices, which are required for the safe operation of the equipment, e.g., brake relays or contactors, emergency stop circuits, safety interlocking, limit switch, and similar devices, shall be monitored in a positive and fail-safe manner, so that malfunctioning of these items of the equipment will not result in an unsafe condition.
8.7.5 Automatic control
8.7.5.1 System design requirements
The system shall comply with the following requirements:
(a) Provision shall be made that no two modes of control are operative at the same time.
(b) Each mode of control to be selected via a keyswitch with the key removable in the
‘off’ position only.
(c) At each control station, on/off and emergency stop controls shall be provided.
8.7.5.2 Safety enclosure
A crane designed to operate under automatic control (i.e. operatorless) shall have its operating area including safety clearances fully enclosed in accordance with the following requirements:
(a) The enclosure shall be not less than 1800 mm high while the distance between the enclosure and any moving part of the crane or its load including recognition of any rope swing or buffer compression distances shall be not less than 450 mm.
(b) The enclosure shall be one of the following constructions:
(i) Sheet metal with all gaps less than 50 mm.
(ii) 50 mm wire mesh of thickness not less than 3 mm.
(iii) 9 mm wire mesh of thickness not less than 1.5 mm.
(iv) Vertical bars not less than 6 mm diameter or tubes not less than 10 mm with clear spacings not greater than 50 mm.
(v) An equivalent enclosure.
(c) The entry gate(s) to the enclosure shall be fitted with an electrical interlocking system that removes electrical power from all crane motions whenever entry to the enclosure
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key switch situated outside the enclosure, preferably with a view over the area of the enclosure.
The interlocking system should include the considerations outlined in AS 4024.1 and in particular should include the following features:
(i) The direct interruption of the power medium (power interlocking).
(ii) The indirect interruption of the power medium by means of a control system (control interlocking).
The interlocking system shall be selected from the following:
(A) Tongue-operated switch or similar device that is designed to be difficult to defeat.
(B) Trapped-key control system (key exchange).
(C) Other interlocking systems given in AS 4024.1, which achieve the equivalent safety features of (A) or (B) above.
(d) The enclosure shall have safety signs in conformance with AS 1319—
(i) mounted externally on every side of the enclosure at a spacing not greater than 25 m cautioning that the automatic crane may move without warning; and (ii) mounted on every access gate forbidding entry without opening a crane isolator
external to the enclosure.
When an automatic crane is operating wholly over an elevated platform, tank or structure that is not less than 1800 mm above the surrounds then a separate enclosure need not be constructed but the access ways to the top of the elevated structure shall comply with Items (c) and (d)(ii) above.
8.7.5.3 System requirements
The electronic equipment used in an automatic control shall comply with Clause 8.7.4 except that movements or actions dictated by the crane operator in Clause 8.7.4 are replaced by the automation programmed outputs.
Any cordless control system used within the automatic control system to communicate to the crane or to communicate between sections within the crane shall comply with Clause 8.7.3.4.
An automatic crane shall have a visual and audible warning system that operates 5 seconds prior to each travel motion and at least the visual warning system shall operate continuously during the operation of each travel motion.
8.7.5.4 Access for power-on faults diagnosis
Where it is necessary for personnel to have access to an automatically controlled crane for the purpose of fault diagnosis or equipment adjustment and this can only be undertaken by operating the crane with personnel within the enclosure, then the following shall apply:
(a) Safe areas shall be provided in which personnel can stand.
(b) Each of these safe areas shall be equipped with an emergency stop that will stop each motion by means of control interlocking.
(c) The automatic control cycle shall be reset from its isolated state by a hold-to-run type switch from a prime safe area within the enclosure.
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8.7.6 Stop functions 8.7.6.1 General
There are three categories of stopping functions:
(a) Category 0: stopping by immediate removal of power to the hoisting machine actuators (i.e. an uncontrolled stop);
(b) Category 1: a controlled stop with power available to the hoisting machine actuators to achieve the stop and then the removal of power when the stop is achieved; and (c) Category 2: a controlled stop with power left available to the hoisting machine
actuators.
NOTE: With the exception of emergency stop and/or emergency switching off, and depending upon the risk assessment, removal of power may be accomplished by the use of either electromechanical or solid-state components.
Category 0, Category 1 or Category 2 stops or combinations shall be provided where indicated by the risk assessment and the functional requirements of the hoisting machine.
Category 0 and Category 1 stops shall be operational regardless of the operating modes and Category 0 shall take priority. Stop functions shall override related start functions.
8.7.6.2 Emergency stop
Except where exempted by Clause 8.10.8, hoisting machines shall have an emergency stop function, which shall at least stop the motion drives. This emergency stop shall function as a category 0 stop and be initiated by a single human action.
The emergency stop function shall comply with the following minimum requirements:
(a) It shall be fail-safe.
(b) The energy source to all motion drives shall be removed as quickly as possible without creating other hazards (e.g., by the provision of mechanical brakes requiring no external energy source for stopping).
(c) It shall override all other functions and operations in all modes.
(d) Reset shall not initiate a restart.
8.8 LIMIT SWITCHES (see also Clause 7.13)