Beckhoff PS3031-4820-0000, Documentation

Page: 17 / 45

Technical data, mounting, wiring
PS3031-4820-0000 17 Version: 1.0
3.6 DC-OK relay contact
This function monitors the output voltage generated by the power supply itself. It is independent of a voltage
fed back from a unit connected in parallel to the power supply output.
The contact closes when the output voltage reaches 90% of the set output voltage.
The contact opens when the output voltage drops more than 10% below the set output voltage.
Short bursts are extended to a signal length of 250 ms. Drops that are shorter
than 1 ms are ignored.
The contact closes again when the output voltage exceeds 90% of the set voltage.
Contact load capacity Maximum 60 Vdc 0.3 A, 30 Vdc 1 A, 30 Vac 0.5 A, ohmic load
Minimum permissible load: 1 mA at 5 Vdc
Insulation voltage
See the table in chapter Dielectric strength [
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29]
Fig. 9: Behavior of the DC-OK relay contact
Nature and source of the danger
The DC-OK function requires the output voltage to reach the rated (=set) level after power-up in or-
der to function as specified.
• If this level is not reached, the overload LED lights up and the DC-OK contact opens. The over-
load LED goes out when the set voltage is reached.
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This is an important condition to be considered especially if the load is a battery, the power sup-
ply is used in parallel or the power supply is used for N+1 redundant systems.