SECTION EIGHT – Safety function RESTART INTERLOCK (Optional)
DS2000 USER’S MANUAL (rev.C)
8.5
8.4 RESTART INTERLOCK CIRCUIT
The restart interlock is provided by redundant interlocking devices acting independently on
the drivers of the power control devices.
8.4.1 HARDWARE CHANNELS
The hardware channels (channel 1 and channel 2) interrupt the auxiliary power supply to the
IGBT drivers via two relays with forcibly guided contacts..
8.4.1.1 MONITORING CHANNEL 1
For monitoring the interlocking system the input signal “Channel 1” and the output signal
“Channel 1 verification” must be checked to have the appropriate status under the following
conditions:
Condition 1: “Channel 1” = 0 “Channel 1 verification” = 1
“Channel 1” = 0 -> 1 “Channel 1 verification”(after a delay of max 100ms) = 0
Condition 2: “Channel 1” = 1 “Channel 1 verification” = 0
“Channel 1” = 1->0 “Channel 1 verification”(after a delay of max 100ms) = 1
The check of condition 2 allows to find the short circuit on the wiring of the NC contact of the
safety relay. When this check is not available it is necessary to follow the wiring procedures
following listed.
When a wrong signal status is monitored, the line contactor must disconnect the drive supply,
taking care of the the release time (max 100 ms) of the signal. An error message must be
available to make the malfunction of the safety circuit visible.
WARNING: In case of malfunction the whole safety circuit need to be checked by qualified
personnel taking into account the necessary safety procedures
8.4.1.2 MONITORING CHANNEL 2
As explained before, the second hardware channel can be requested by the product standard
or can be used to improve the reliability of the safety category.
For monitoring the interlocking system the input signal “Channel 2” and the output signal
“Channel 2 verification” must be checked to have the appropriate status under the following
conditions:
Condition 1: “Channel 2” = 0 “Channel 2 verification” = 1
“Channel 2” = 0 -> 1 “Channel 2 verification”(after a delay of max 100ms) = 0
Condition 2: “Channel 2” = 1 “Channel 2 verification” = 0
“Channel 2” = 1->0 “Channel 2 verification”(after a delay of max 100ms) = 1
The check of condition 2 allows to find the short circuit on the wiring of the NC contact of the
safety relay. When this check is not available it is necessary to follow the wiring procedures
following listed.
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