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safety issue. This situation does not apply to asynchronous
motors.
5.3.1 Liability Conditions
The user is responsible for ensuring that personnel know
how to install and operate the Safe Torque Off function by:
•
Reading and understanding the safety regulations
concerning health and safety/accident prevention.
•
Understanding the generic and safety guidelines
given in this description and the extended
5
5
description in the VLT
Safe Torque Off Operating Guide.
•
Having a good knowledge of the generic and
safety standards for the specific application.
The user is defined as integrator, operator, service, and
maintenance staff.
5.3.2 Additional Information
For more information regarding Safe Torque Off, including
installation and commissioning, refer to the VLT
Converters – Safe Torque Off Operating Guide.
5.3.3 Installation of External Safety Device
in Combination with VLT
Thermistor Card MCB 112
If the ex-certified thermistor module MCB 112, which uses
terminal 37 as its safety-related switch-off channel, is
connected, then the output X44/12 of MCB 112 must be
AND-ed with a safety-related sensor (emergency stop key
or safety-guard switch) that activates Safe Torque Off. The
output to Safe Torque Off terminal 37 is high (24 V) only if
both the signal from MCB 112 output X44/12 and the
signal from the safety-related sensor are high. If at least 1
of the 2 signals are low, then the output to terminal 37
must be low, too. The safety device with this AND logic
itself must conform to IEC 61508, SIL 2. The connection
from the output of the safety device with safe AND logic
to Safe Torque Off terminal 37 must be short circuit
protected. Illustration 5.1 shows a restart input for the
external safety device. In this installation, for example, set
[7] PTC 1 & Relay W or [8] PTC 1 & Relay A/W in
parameter 5-19 Terminal 37 Safe Stop. Refer to the VLT
Thermistor Card MCB 112 Operating Instructions for further
details.
20
®
VLT
Parallel Drive Modules
®
Frequency Converters –
®
Frequency
®
PTC
®
PTC
Danfoss A/S © 6/2016 All rights reserved.
Hazardous
Non-Hazardous Area
Area
PTC Thermistor Card
X44/
1 2 3 4 5 6 7 8 9 10 11 12
Digital Input
PTC
e.g. Par 5-15
Sensor
12 13 18 19 27 29 32 33 20 37
Par. 5-19
Terminal 37 Safe Stop
Illustration 5.1 Illustration of the Essential Aspects for
Installing a Combination of a Safe Torque Off Application and
an MCB 112 Application
Parameter settings for external safety device
with MCB 112
If MCB 112 is connected, then selections [4] through [9]
become possible for parameter 5-19 Terminal 37 Safe Stop
(Terminal 37 Safe Torque Off).
Selections [1]* Safe Stop Alarm and [3] Safe Stop Warning in
parameter 5-19 Terminal 37 Safe Stop are still available, but
are used only for installations without MCB 112 or any
external safety devices. If [1]* Safe Stop Alarm or [3] Safe
Stop Warning in parameter 5-19 Terminal 37 Safe Stop is
selected by mistake and MCB 112 is triggered, then the
frequency converter reacts with alarm 72, Dangerous Failure
and coasts the frequency converter safely without an
automatic restart.
Selections [4] and [5] parameter 5-19 Terminal 37 Safe Stop
are only selected when MCB 112 uses the Safe Torque Off.
If selections [4] PTC 1 Alarm or [5] PTC 1 Warning in
parameter 5-19 Terminal 37 Safe Stop is selected by mistake
and the external safety device triggers Safe Torque Off, the
frequency converter reacts with alarm 72, Dangerous Failure
and coasts the frequency converter safely without an
automatic restart.
Selections [6] through [9] in parameter 5-19 Terminal 37
Safe Stop must be selected for the combination of external
safety device and MCB 112.
MCB 112
DI
DI
Safe Stop
Safety Device
SIL 2
Safe AND Input
Safe Output
Manual Restart
MG37N102
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