Notes For Compliance To Functional Safety Standard - Fuji Electric FRENIC-HVAC User Manual

Notes
11.1.4.2 for compliance to Functional Safety Standard
1) Wiring for terminals [EN1] (Enable input 1) and [EN2] (Enable input 2)
- [EN1]/[EN2] and [PLC] are terminals prepared for connection of safety related wires; therefore, careful
wiring should be performed to ensure that no short-circuit(s) can occur to these terminals.
- For opening and closing the hardware circuit between terminals [EN1]/[EN2] and [PLC], use safety
approved components such as safety relays that comply with EN ISO13849-1 PL=d Cat. 3 or higher to
ensure a complete shut off.
- It is the responsibility of the machinery manufacturer to guarantee that a short-circuiting or other fault
does not occur in wiring of external safety components between terminals [EN1]/[EN2] and [PLC].
Fault examples:
• Terminals [EN1]/[EN2] and [PLC] are short-circuited due to the wiring being caught in the door of the
control panel so that a current continues to flow in terminal [EN1]/[EN2] although the safety
component is OFF and therefore the safety function may NOT operate.
• The wiring is in contact with any other wire so that a current continues to flow in terminal
[EN1]/[EN2] and therefore the safety function may NOT operate.
2) Notes for Safe Torque Off (STO) functional safety function
- When configuring the product safety system with this Safe Torque Off (STO) function, make a risk
assessment of not only the external equipment and wiring connected to terminals [EN1] and [EN2]
(Enable input 1 and Enable input 2) but also the whole system including other equipment, devices and
wiring, because it is required by the machine directive that the whole system conforms to the safety
requirements under the machine manufacturer's responsibility.
In addition, as preventive maintenance, the machinery manufacturer must perform periodical
inspections to check that the product safety system properly functions.
- The inverter has been designed according to pollution degree 2 requirements. Therefore, in order to
bring the inverter into compliance with Functional Safety Standard, it is necessary to install the inverter
on a control panel with the enclosure rating of IP54 or above.
- To bring the inverter into compliance with Functional Safety Standard, it is necessary to bring it into
compliance with European Standards EN61800-5-1 and EN61800-3.
- This Safe Torque Off (STO) function coasts the motor to a stop. When a mechanical brake is used to
stop or hold the motor for the sake of the product safety system of whole system, do not use the inverter's
control signals such as output from terminal [Y]. Using control signals does not satisfy the safety
standards because of software intervention. Use safety relay units complying with EN ISO13849-1
PL=d Cat.3 or higher to activate mechanical brakes.
- The safety shutdown circuit between terminal [EN1] and [EN2] input sections and inverter's output
shutdown section is dual-configured (redundant circuit) so that an occurrence of a single fault does not
detract the Safe Torque Off (STO).
If a single fault is detected in the safety shutdown circuit, the inverter coasts the motor to a stop even
with the [EN1]-[PLC] and [EN2]-[PLC] states being ON, as well as outputting an alarm to external
equipment. Note that the alarm output function is not guaranteed to all single faults. It is compliant with
EN ISO13849-1 PL=d Cat. 3.
- The Safe Torque Off (STO) function does not completely shut off the power supply to the motor
electrically. Before starting wiring or maintenance jobs, be sure to disconnect the input power to the
inverter and wait at least 5 minutes.
3) Test of Safe Torque Off (STO) functional safety function
- In application where no regular activation of the Safe Torque Off (STO) function is guaranteed, check at
least once a year that the Safe Torque Off (STO) function works correctly.
4) At power up
- At power up ensure that the terminals [EN1] and [EN2] are not short circuited to PLC (or +24VDC).
This allows executing a diagnostic of the functional safety function circuit.
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