273
Safe Stop option
Section 13-10
13-10 Safe Stop option
To realize a Safe Stop configuration in accordance with Safe Torque Off (STO)
EN-IEC 6206:20051 SIL 2 & EN-ISO 13849-1, the following three parts need
to be attended to:
1.
Inhibit trigger signals with safety relay K1 (via Safe Stop option board).
2.
Enable input and control of VSD (via normal I/O control signals of VSD).
3.
Power conductor stage (checking status and feedback of driver circuits and
IGBT’s).
To enable the VSD to operate and run the motor, the following signals should
be active:
•
"Inhibit" input, terminals 1 (DC+) and 2 (DC-) on the Safe Stop option
board should be made active by connecting 24 V
DC
to secure the supply
voltage for the driver circuits of the power conductors via safety relay K1.
See also Fig. 124.
•
High signal on the digital input, e.g. terminal 10 in Fig. 124, which is set to
"Enable". For setting the digital input please refer to section 11-5-2, page
198.
These two signals need to be combined and used to enable the output of the
VSD and make it possible to activate a Safe Stop condition.
Note
The "Safe Stop" condition according to EN-IEC 62061:2005 SIL 2 &
EN-ISO 13849-1:2006, can only be realized by de-activating both the "Inhibit"
and "Enable" inputs.
When the "Safe Stop" condition is achieved by using these two different meth-
ods, which are independently controlled, this safety circuit ensures that the
motor will not start running because:
•
The 24V
DC
signal is taken away from the "Inhibit" input, terminals 1 and 2,
the safety relay K1 is switched off.
The supply voltage to the driver circuits of the power conductors is
switched off. This will inhibit the trigger pulses to the power conductors.
•
The trigger pulses from the control board are shut down.
The Enable signal is monitored by the controller circuit which will forward
the information to the PWM part on the Control board.
To make sure that the safety relay K1 has been switched off, this should be
guarded externally to ensure that this relay did not refuse to act. The Safe
Stop option board offers a feedback signal for this via a second forced
switched safety relay K2 which is switched on when a detection circuit has
confirmed that the supply voltage to the driver circuits is shut down. See Table
39 for the contacts connections.
To monitor the "Enable" function, the selection "RUN" on a digital output can
be used. For setting a digital output, e.g. terminal 20 in the example Fig. 124,
please refer to section 11-5-4, page 207 [540].
When the "Inhibit" input is de-activated, the VSD display will show a blinking
"SST" indication in section D (bottom left corner) and the red Trip LED on the
Control panel will blink.
To resume normal operation, the following steps have to be taken:
•
Release "Inhibit" input; 24V
DC
(High) to terminal 1 and 2.
•
Give a STOP signal to the VSD, according to the set Run/Stop Control in
menu [215].
•
Give a new Run command, according to the set Run/Stop Control in menu
[215].
Summary of Contents for SX-F
Page 2: ......
Page 14: ...6 Table of contents...
Page 20: ...12 Glossary Section 1 6...
Page 32: ...24 Cabinet mounting Section 2 3...
Page 58: ...50 Connecting options Section 5 6...
Page 72: ...64 Load Monitor and Process Protection 400 Section 7 5...
Page 74: ...66 EMC standards Section 8 1...
Page 266: ...258 System Data 900 Section 11 9...
Page 274: ...266 Maintenance Section 12 3...
Page 284: ...276 Liquid cooling Section 13 12...
