Danfoss VLT FC 102 Series Design Manual page 22

Introduction to VLT® HVAC D...
The adjustable frequency drive is guaranteed not to restart
2 2
creation of a rotational field by an internal fault (in
accordance with Cat. 3 PL d acc. EN ISO 13849-1 and SIL 2
acc. EN 62061). After activation of Safe Torque Off, the
adjustable frequency drive display shows the text Safe
Torque Off activated. The associated help text says "Safe
Torque Off has been activated". This means that the Safe
Torque Off has been activated, or that normal operation
has not been resumed yet after Safe Torque Off activation.
NOTICE!
The requirements of Cat. 3/PL "d" (ISO 13849-1) are only
fulfilled while 24 V DC supply to terminal 37 is kept
removed or low by a safety device, which itself fulfills
Cat. 3/PL "d" (ISO 13849-1). If external forces act on the
motor, e.g., in case of vertical axis (suspended loads) -
and an unwanted movement, for example caused by
gravity, could cause a hazard, the motor must not be
operated without additional measures for fall protection.
For example, mechanical brakes must be installed
additionally.
To resume operation after activation of Safe Torque Off,
first reapply 24 V DC voltage to terminal 37 (text Safe
Torque Off activated is still displayed), then create a reset
signal (via bus, Digital I/O, or [Reset] key on inverter).
By default, the Safe Torque Off functions is set to an
Unintended Restart Prevention behavior. This means, in
order to terminate Safe Torque Off and resume normal
operation, the 24 V DC must first be reapplied to Terminal
37. Subsequently, send a reset signal (via Bus, Digital I/O,
or [Reset] key).
The Safe Torque Off function can be set to an Automatic
Restart Behavior by setting the value of 5-19 Terminal 37
Safe Stop from default value [1] to value [3]. If a MCB 112
Option is connected to the adjustable frequency drive,
then Automatic Restart Behavior is set by values [7] and
[8].
Automatic Restart means that Safe Torque Off is
terminated and normal operation is resumed as soon as
the 24 V DC is applied to Terminal 37, and no reset signal
is required.
20
Design Guide
Automatic Restart Behavior is only allowed in one of the
two situations:
2.6.2 Installation of External Safety Device
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 the safety-related sensor (such as emergency
stop button, safety-guard switch, etc.) that activates Safe
Torque Off. This means that 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 one of the two signals is LOW,
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. See Figure 2.7.
Danfoss A/S © Rev. 06/2014 All rights reserved.
WARNING
1. The Unintended Restart Prevention is
implemented by other parts of the Safe Torque
Off installation.
2. A presence in the dangerous zone can be
physically excluded when Safe Torque Off is not
activated. In particular, paragraph 5.3.2.5 of ISO
12100-2 2003 must be observed.
in Combination with MCB 112
MG11BC22