HDT NTT 240, Инструкция по установке и эксплуатации

Страница: 118 / 130

118
Installation and user guide
Rev: 4.0
NTT 240/460
S.T.O. safety circuit
4. STO does not provide electrical isolation of the drive output.
If access is needed to the electrical connections of the motor circuit, an approved isolation device must isolate
the drive power input. The required discharge time that must spent before access is permitted is usually about 10
minutes.
5. STO cannot detect if the two enable inputs have been energised both inadvertently.
If both the two input channel STO IN 1, STO IN 2 have been inadvertently connected to a positive digital signal
within the specified range, the drive will be enabled.The probability of this happening is very low. However, to
ensure the maximun integrity, during installation the wiring must be protected from accidental contact with
digital signals or supplies.
6.
Special Requirement
The output of SDP should be monitored at every intervention of the safety circuit by user. If the STO output is not
active, with both the two STO inputs de-energized, it means that at least one of the two safety circuits is faulty and
therefore the drive must be send to repaired. STO output is managed by microcontroller and for this reason, it’s
not considered as a secure output.
STO output follows graphs below:
SPD IN 1 channel
SPD IN 2 channel
SPD output
(OUT1-2)
SPD IN 1 channel
SPD IN 2 channel
SPD output
(OUT1-2)
>5ms 100ms 100ms
FA08
Safe State Drive not OK Drive OK Drive not OK
FA08
Safe State
FA18 o FA23
Avaria Hardware
De-energize condition for SPD IN 1 e SPD IN 2 channels
Drive not OK Drive OK
Drive OK
>5ms 100ms
FA08
Safe State
FA08
Safe State
FA18 o FA23
Avaria Hardware
Energize condition for SPD IN 1 e SPD IN 2 channels
Drive not OK
100ms
FA08
Safe State
A special requirement is needed for the use of protected wiring to the two enable (STO IN 1, STO IN 2) inputs, in
order to exclude the possibility of a short-circuit to a positive supply (see box below). Is reccomanded, under UNI
EN ISO 13849-2 law, the use of protected wiring.
PROTECTED WIRING
Protected wiring is arranged so that no short circuit is credible to any source of voltage which might cause a
failure in the unsafe direction. A practical implementation is either:
Fully segregated in dedicated trunking etc. or
Screened, with the screen connected to ground, in a positive-logic grounded control circuit.
7. Caratteristiche dei contatti esterni
With mechanical contacts, it’s mandatory that activation or deactivation latency time will be less than 100ms
(including any rebounds for mechanical contacts within 20ms ). It’s recommended to use contact that allows
activation and deactivation delay to be less than 50ms , or please use contacts that are granted by external STO
Safety Function approved modules.