Siemens SIMATIC ET 200C, Manual

Page: 308 / 333

C-2
ET 200C Distributed I/O Station
EWA 4NEB 812 6119-02b
C.1 Active and Passive Faults in Automation Equipment
Depending on the particular task for which the electronic automation equip-
ment is used, both active as well as passive faults can result in a dangerous
situation. For example, in drive control, an active fault is generally dangerous
because it can result in an unauthorized startup of the drive. On the other
hand, a passive fault in a signalling function can result in a dangerous operat-
ing state not being reported to the operator.
The differentiation of the possible faults and their classification into danger-
ous and non-dangerous faults, depending on the particular task, is important
for all safety considerations in respect to the product supplied.
!
Warning
In all cases where a fault in automation equipment can result in severe
personal injury or substantial property damage, i.e., where a dangerous fault
can occur, additional external measures must be taken or equipment
provided to ensure or force safe operating conditions even in the event of a
fault (e.g., by means of independent limit monitors, mechanical interlocks,
etc.).
If you are carrying out measurement or testing work on the ET 200C distrib-
uted I/O station, you must adhere to the rules and regulations contained in
the VBG 4.0 Accident Prevention Regulations of the German employers li-
ability assurance association (“Berufsgenossenschaften”). Pay particular
attention to paragraph 8, “Permissible exceptions when working on live
parts”.
Repairs may only be carried out by Siemens service personnel or Siemens-
authorized repair shops.
Active and Passive
Faults
Procedures for
Maintenance and
Repair
Safety-Related Guidelines