DN3PD1
Function description
8 18-09-27 / 33pd02-V0743
4 Function description
The two-channel evaluation unit of the safety switchgear module measures the frequency of the effective rotat-
ing field of the motor at the measuring terminals L1, L2, L3.
If the parameterized switching threshold frequencies are exceeded or undershot (V-LIMIT 1 and V-LIMIT 2), or an
internal or external fault exists, the enabling current paths 13/14, 23/24 open immediately. The device is in safe
switching state.
The monitoring of V-LIMIT 1 can be deselected. Then the output contacts remain closed at standstill.
Asynchronous motors have a load-dependent slip between the motor speed and the rotating field frequency. This
must be observed by the configuration of the switching threshold (V-LIMIT 1 and V-LIMIT 2).
Switching threshold
Two switching thresholds are configurable.
V-LIMIT 1: minimum speed
If V-LIMIT 1 is undershot, the output contacts (13-14 / 23-24) switch off.
They switch on again after the acknowledgment via the acknowledgment input Q.
Depending on the acknowledgment mode, the switch-on-conditions differ. Please note the chapter
"Function diagram".
V-LIMIT 2: Maximum speed
If V-LIMIT 2 is exceeded, the output contacts (13-14 / 23-24) switch off.
They switch on again after the acknowledgment via the acknowledgment input Q, if V-LIMIT 2 (minus hysteresis)
is undershot.
Switching on takes place at the earliest after 0.5 seconds. (see chapter minimum switch-off time)
Start-up monitoring
The startup monitoring tA is a time limit within which the actual speed must be greater than V-LIMIT 1. If the mini-
mum speed is not reached during this time, the enable current path opens again.
The start-up monitoring time is fixed and is 60s. It is not retriggerable, it cannot be restarted while it is running.
The start-up monitoring time starts
• In case of manual acknowledgment: with the falling edge of the acknowledge signal
• In case of automatic acknowledgment: if the actual speed is> 1Hz
The startup monitoring is omitted if V-LIMIT 1 has been deselected.
Minimum switch-off time
The minimum switch-off time tmin is the time that the enable current path is at least open after triggering before it
switches on again. It is 0.5s.
Acknowledge function
• With the acknowledgment function, the enable current path is switched on again after a shutdown due to
underspeed or overspeed.
• The acknowledgment takes place via the input Q.
• Automatic or manual acknowledgment is possible.
• With automatic acknowledgment, the Q input must always be connected to 24V DC.
• A manual acknowledgment takes place after a falling signal edge at the input Q (t
Q ≥ 200ms and ≤ 10s).
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