Bitzer VARIPACK FD+6 Instructions De Service page 25

Information
The STO function is a factory built-in and tested
function.
Repairs on VARIPACK frequency inverters
equipped with STO function may only be carried
out by authorized staff.
Any unauthorized attempt to repair or dismantle
the VARIPACK will void the guarantee and may
impair the STO function.
As soon as the VARIPACK frequency inverter
will detect an internal STO error, it must be elim-
inated immediately.
NOTICE
!
!
Defined switching points are no longer guaran-
teed if lines are too long or incorrectly installed.
Maximum line length to terminals X10/01,
X10/03, X10/05 and X10/06: 25 m!
• For high safety requirements, two independent STO
control channels have been implemented in the
hardware. The STO circuit is designed such that
upon occurrence of an error in a channel, the second
channel ensures that no inadvertent operation of the
VARIPACK frequency inverter takes place.
• The activated STO function overrides all attempts to
start the compressor. This means that if the STO
function is switched by one or both STO control in-
puts, the compressor will not start. This is also true
if, for example, an internal software error should res-
ult in a start attempt.
Safety specifications:
According to EN ISO13849-1 and EN61800-5-2, the
VARIPACK frequency inverters have the following
safety characteristics:
Safety levels reached by the frequency inverters
①
SIL safety integrity level
PL performance level
Underlying safety characteristics ②
PFH Average probability of a danger-
ous failure per hour
MTTF Average time until a dangerous
d
error is reached
DC diagnostic coverage
SFF Overall proportion of safe failures 99% →
CB-100-2
T
M
Tab. 4: VARIPACK safety characteristics according to EN
ISO12849-1 and EN61800-5-2
①: The indicated safety levels and underlying safety
characteristics are applicable to the VARIPACK fre-
quency inverter if both STO inputs can be activated in-
dependently of each other. Depending on the integra-
tion into the system, the safety level of the complete
system can be lower and must be calculated by the
system manufacturer.
②: The safety characteristics used for determining the
safety level are listed in order to allow calculation of the
complete system.
③: The standard EN ISO13849 limits the MTTF
to 100 years.
STO function testing
During the commissioning and during an interval to be
defined by the system manufacturer on the basis of a
risk assessment, all safety devices and the functions of
the entire safety chain must be checked for correct
functioning. Based on the schematic wiring diagrams
(see chapter Operating modes, page 20), the STO
function including the system integration can be
checked using the following procedure:
• Put the compressor into operation.
• Trigger the high-pressure switch (F5).
– The compressor must be switched off immediately
and the frequency inverter must send an STO
fault message.
• Close the high pressure switch and/or the safety
chain.
– The STO fault is reset and the compressor is re-
started after a defined time delay.
SIL3
PLe
-9
2,3 x 10
100 years
③
98.6% →
high
average
service life 20 years
value
d
25