Current-Relay STW12

Current Relay for AC-Detection, 12-channel, 12 open collector outputs, Single evaluation and OR-Circuit, open printed circuit board

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Part number

DC 20 - 30 V

Product description


The current relay STW12 monitors the current flow yes/no of up to 12 alternating-current circuits. If there is an AC-current of ≥1 A through a connected transformer STWA 1, the according output transistor switches and the yellow LED lights up. 

All the OR inputs are linked at the same time. If a current is identified in at least one of the monitored current circuits, a relay (1 changeover contact) picks up. 

The STW12 is installed at an open printed circuit board. The lower part can be used for snapfastening on a 35 mm DIN-rail or for screw fastening (option). The supply voltage is DC 24. This voltage can be used at the same time for inquiry of the output transistors. When requesting the outputs in 2 groups in multiplex operation, only 8 I/Os of the PLC are needed.

  • 12 inputs (for transformer STWA1)
  • 2 of these inputs with adjustable switching threshold AC 0,5...5 AA
  • 12 outputs (Open Collector) max. DC 40 V/40 mA
  • relay OR-linked (of all 12 inputs)
  • LED displays (1/channel)
  • Multiplex operation possible

The current relay STW12 is used where AC-current yes/no has to be evaluated, however, the exact value of the current is not relevant. Examples are the control of machines in suction plants or monitoring of the mode of operation of loads (on, off or damaged). The STW12 is suitable in particular for being used in connection with a PLC.


Technical Data

Power supply Us


DC 20 - 30 V, < 2 VA




12-channel single/OR


Transformer input


1…12, type STWA 1


Overload cap.continous/max 10s


100 A / 300 A


Switching points E1, E2


adjustable, AC 0,5...5 A




± 20%


Switching points E3...E12


on ≤ AC 1 A
off ≥ AC 0,3 A


Switch-off delay


10 sec.


Switch-on delay


approx. 0,5 sec.


Output relay


1 CO, 12 x Open-Collector


Type of contact


type 2 see general technical informations


Open Collector


max. DC 40 V/40 mA


Testing conditions


see general technical informations


rated ambient temperature range




Dimensions H x B x T


design V 6: 90 x 105 x 32 [mm], 37-pole




on 35 mm DIN rail according to DIN EN 50 022 or with screws M4 (option)


Protection housing / terminals


IP 30 / IP 20




approx. 135 g