Product note

DCS800 „Safe Torque Off“ option

Principle Performance level and SIL level are never related to a com-
For small cleaning type work or inspection of production machine, plete drive, the values are related to a certain function (safety
it must be possible for machine operators to prevent unexpected function).
start up of drive motors. Probability of a dangerous failure per hour

10-4 10-5 10-6 10-7 10-8

The armature converter is disconnected from supply. Typically 3y10-5
PL
air circuit breakers or contactors are used on AC side. Very big ISO 13849-1 a b c d e
drives are typically equipped with High speed DC breakers which Low Risk High Risk

can also be used to open and prevent armature current. The SIL no special
safety
IEC 61508 requirements
1 2 3
pure blocking of field current as well as blocking of firing pulses of
9000 900 90 9 0.9
armature bridge does not guarantee NO TORQUE AT SHAFT. The
Dangerous failures per year and 10 000 systems
solution provides NO torque at the shaft, BUT it does not provide
electrical mains OFF (no voltage) of all live parts (no voltage at Product description
motor terminals). DCS800 STO is an option for DCS800-A enclosed converter
as well as DCS800‑E panels or DCS800‑R TYRAK revamp
Standards kits. DCS800 option STO circuit is built on redundant wiring,
Under machine directive EN 60204-1 the safety Standard EN monitoring of redundant wring and monitoring by safety relays
954-1 with the categories B,1,2,3 are well known. Dold BD5935. The activation is displayed by Feedback lamp.
The circuits designed under the safety principles in accor-
2009 EN 954-1 is replaced by new Safety standard EN ISO dance with EN ISO 13849-1.
13849-1. The content is influenced by EN 61508 Control
devices and EN 62061 for machine devices. Safemaster module BD 5935
12 / 2009 –– According to EU Directive for machines 98/37/EG
Machines
Special

Standard Type C (Reference) new standard Type C –– According to IEC/EN 60204-1

Safety Today 11/2009
–– Safety category 4 according to EN 954-1
Systemintegrator OEM

Requirements

EN 954-1
3 Years
Transition –– Output: optionally 1 NO / 1 NC or 3 NO / 1 NC
EN ISO 13849-1
–– Gold plated contacts to switch
11/2006 low loads
EN IEC 62061
–– 1- or 2-channel connection
2005

IEC 61800-5-2 Variable speed drives –

–– Line fault detection on ON push-
Component supplier

part 5-2: Safety – functions

button
(ABB Drives)

8 / 2007

IEC 61508 –– Operating state display

New machine directive
2006/42/EC –– LED display for channels 1 and 2
–– Overvoltage and short circuit
The new standards are also adopted by local standards. protection
–– Optionally automatic ON function
OSHA for north America • GOST R for Russia • CCC for when the operating voltage is applied or activation via the
China • OH&S for Australia. ON pushbutton
–– Optionally cross fault detection in emergency-stop
The safety is given in Safety Integrity Level (SIL) or Perfor-
mance Level (PL). Approvals and marking 1)
*
1)
pending
Deutschland Canada / USA * see variants
The new standard EN ISO 13849-1 takes care on prevention
of hazard situation by calculation of malfunction of electric
devices. The PL calculation is based on MTBF of electronic
devices multiplied with size of human injury. The calculation
takes also in account the wiring, how devices are wired (e.g.
redundant or not redundant) and discoverage of fault (contin-
ues fault monitoring or fault monitoring only during boot).
Function description of option STO E-Stop
The circuit of „Safe Torque Off“ (STO) is an option of enclosed The function E-Stop means electrical stop (braking) as fast as
converter DCS800-A, DCS800-E Drive panel or DCS800-R possible and has nothing to do with STO.
TYRAK revamp kit. This safety function provides the protec-
tion „prevention of unexpected start up” as in Standard DIN
EN 1037 described. door open
K1
The safety function is designed according category 3 of
EN ISO 13849-1.
The principle behind the Function „Safe Torque Off“ is a pre- „ prevention of start up
vention of any torque at the motor shaft by opening armature „ More than one switch
Maintenance
in series Safety switch
circuit.

The design is based on two independent circuits by removing „ E STOP

„ Categorie 1
Digital input 7 (=0) the current is suppressed as fast as pos- „ Probaly one more E-Stop E-Stop
safty circuit Botton
sible and later on the firing pulses are blocked. The second Timer
E-Stop command = ramp down
channel is the opening the main circuit breaker, AC contactor
or high-speed DC breaker. In case of different stop categories EN 60204 (e.g. ramp stop)
One single fault does not disturb the safety function. If a fault the DCS800 STO solution can be combined with E-Stop cir-
is detected the ON is blocked and Reset is not possible. Not cuit and E-Stop command.
all possible (device) faults can be discovered (DC diagnostic
coverage). Sometimes the E-Stop circuit is also equipped with a safety
relay, which requires a different second relay.

Certified E-Stop requires a separate approval.

© Copyright 2009 ABB. All rights reserved. Specifications subject to change without notice. PDC6 EN REVB 2011
Ratings
PL = d
Details:
MTTF d = 69 years
= 1/1.8*10-7 h
DC avg = 61%
Structure = Category 3
CCF = 90

For more information please contact:

www.abb.de/motors&drives
dc-drives@de.abb.com