Terminal 37 Safe Stop Function - GE AF-650 GP Design And Installation Manual

Application Setup Examples
Abbrev. Ref.
Cat. EN 954-1
FIT
HFT IEC 61508
MTTFd EN ISO
13849-1
PFH IEC 61508
6 6
PL EN ISO
13849-1
SFF IEC 61508
SIL IEC 61508
STO EN
61800-5-2
SS1 EN 61800
-5-2
Table 6.24 Abbreviations related to Functional Safety
The PFDavg value (Probability of Failure on Demand)
Failure probability in the event of a request of the safety
function.

6.10.1.1 Terminal 37 Safe Stop Function

Safe stop disables the control voltage of the power
semiconductors of the adjustable frequency drive output
stage which in turn prevents generating the voltage
required to rotate the motor. When the Safe Stop (T37) is
activated, the adjustable frequency drive issues an alarm,
trips the unit, and coasts the motor to a stop. Manual
restart is required. The safe stop function can be used for
stopping the adjustable frequency drive in emergency stop
situations. In the normal operating mode when safe stop is
not required, use the adjustable frequency drives regular
stop function instead. When automatic restart is used – the
requirements according to ISO 12100-2 paragraph 5.3.2.5
must be fulfilled.
Liability Conditions
It is the responsibility of the user to ensure personnel
installing and operating the Safe Stop function:
6-30
AF-650 GP
Description
Category, level "B, 1-4"
Failure In Time: 1E-9 hours
Hardware Fault Tolerance: HFT = n means,
that n+1 faults could cause a loss of the
safety function
Mean Time To Failure - dangerous. Unit:
years
Probability of Dangerous Failures per
Hour. This value shall be considered if the
safety device is operated in high demand
(more often than once per year) or
continuous mode of operation, where the
frequency of demands for operation made
on a safety-related system is greater than
one per year.
Discrete level used to specify the ability of
safety related parts of control systems to
perform a safety function under
foreseeable conditions. Levels a-e
Safe Failure Fraction [%]; Percentage part
of safe failures and dangerous detected
failures of a safety function or a
subsystem related to all failures.
Safety Integrity Level
Safe Torque Off
Safe Stop 1
TM
Design and Installation Guide
•
Read and understand the safety regulations
concerning health and safety/accident prevention
•
Have a good knowledge of the generic and safety
standards applicable to the specific application
User is defined as: integrator, operator, servicing,
maintenance staff.
Standards
Use of safe stop on terminal 37 requires that the user
satisfies all provisions for safety including relevant laws,
regulations and guidelines. The optional safe stop function
complies with the following standards.
EN 954-1: 1996 Category 3
IEC 60204-1: 2005 category 0 – uncontrolled stop
IEC 61508: 1998 SIL2
IEC 61800-5-2: 2007 – safe torque off (STO)
function
IEC 62061: 2005 SIL CL2
ISO 13849-1: 2006 Category 3 PL d
ISO 14118: 2000 (EN 1037) – prevention of
unexpected startup
Protective Measures
•
Safety engineering systems may only be installed
and commissioned by qualified and skilled
personnel
•
The unit must be installed in an IP54 cabinet or
in an equivalent environment. In special
applications, a higher IP degree may be necessary
•
The cable between terminal 37 and the external
safety device must be short circuit protected
according to ISO 13849-2 table D.4
•
If any external forces influence the motor axis
(e.g. suspended loads), additional measures (e.g. a
safety holding brake) are required in order to
eliminate hazards.
DET-767A