Bosch Rexroth 4WRPEH6 3X Operating Instructions Manual page 16

16/44 Safety instructions
Type of Valve type
actuation
Direct actuated 4WRPEH10
valves 4WRPEH6
4WRPE6
4WRPE10
Pilot-operated 4WRLE
valves
Bosch Rexroth AG, 4WRPEH6_3X, 4WRPEH10_3X, 4WRPE6_3X, 4WRPE10_3X, 4WRLE_4X; RE 29118-B/09.2021
2.7.2 Limits of the safety-related parts
Assessment of the valve with IO-Link interface according to ISO 13849-2:
• Potential failures or unidentified error states of the valve with IO-Link interface
always require application-dependent and suitable system-related measures
according to EN 13849-1 (see chapter 2.7.1).
• When using the valve with IO-Link interface in compliance with categories
2 or 3 according to EN13849-1, adequate cyclic diagnosis or monitoring of the
valve function outside of the valve by the control system must be implemented
by the machine integrator. Without suitable diagnostic measures, only cat.
B or 1 according to EN13849-1 can be reached.
2.7.3 Residual risks/error states
The following residual risks or error states may occur and must be taken into
account by appropriate system-related measures:
• Complete failure of the electronics of the valve
• Faulty output of operating states
• Uncontrolled movement of the valve control spool (may lead to uncontrolled
movement of the cylinder)
• Fuse protection in the case of short-circuits in the electronics of the valve with
IO-Link interface by means of appropriate protection and design of the supply line
(fuse protection against currents >4 A).
2.7.4 MTTF , DC, CCF
d
For valves with IO-Link interface, MTFF
information specified in the table using the following formula:
MTTF

dGesamt
MTTF
Table 6: Information for calculation of the MTTF
MTTF values
d
Hydraulic Switch-off path
components
150 years 1000 years
75 years 1000 years
valves can be calculated according to the
d
1
1 1

MTTF
dHydraulikteil dAbschaltpfad
value
d
SELV/PELV power supply
unit + safe IO-Link terminal
MTTF value depending
d
on manufacturer of power
supply unit + safe IO-Link
terminal
(MTTF = approx. 2 x MTBF)
d
e.g. MTBF = 500000 h
→ MTTF value =
d
approx. 1 mio. h (114 years)
1

MTTF
dNetzteil
MTTF value Example of total
d
Valve and MTTF value
d
electronics (for power supply
switch-off path unit + IO-Link
(without terminal with MTTF
additional value of 1 mio. h)
components)
130 years 60
69 years 43
d