130BC974.10
12
37
K 1
K 1
K 1
4
1
3
2
Illustration 4.27 STO Category 4 Example
1
Frequency converter
2
[Reset] key
3
Safety relay
4
Emergency stop
Table 4.31 Legend
Paralleling of Safe Stop input the one Safety Relay
Safe Stop inputs T37 (STO) may be connected directly
together if it is required to control multiple frequency
converters from the same control line via one Safety Relay
(see
). Connecting inputs together increases
the probability of a fault in the unsafe direction. A fault in
one frequency converter can result in all frequency
converters becoming enabled. The probability of a fault for
T37 is so low, that the resulting probability still meets the
requirements for SIL2.
130BC975.10
12
37
1
20
1
1
3
4
5
2
37
20
37
20
Illustration 4.28 Paralleling of Multiple Drives Example
1
Frequency converter
2
24 V DC
3
[Reset] key
4
Safety relay
5
Emergency stop
Table 4.32 Legend
WARNING
Safe Stop activation (that is, removal of 24 V DC voltage
supply to terminal 37) does not provide electrical safety.
The Safe Stop function itself is therefore not sufficient to
implement the Emergency-Off function as defined by EN
60204-1. Emergency-Off requires measures of electrical
isolation, for example, by switching off mains via an
additional contactor.
1.
Activate the Safe Stop function by removing the
24 V DC voltage supply to the terminal 37.
2.
After activation of Safe Stop (that is, after the
response time), the frequency converter coasts
(stops creating a rotational field in the motor).
The response time is typically less than 10ms.
Application Examples
VLT
®
Decentral Drive FCD 302
MG04H102 - VLT
®
is a registered Danfoss trademark
71
4
4