What are the relays state of ZBRRA receiver when powered off?

1. What you need to know

When a Harmony ZBRRA receiver has no supply voltage, both output relays sit in their de-energized position: the NC contacts 11-12 and 21-22 are closed, and the NO contacts outputs 12-14 and 22-24 are open. If the supply is cut off while an output is ON, the contacts outputs return to this same de-energized state. Output states are not retained through a power loss; transmitter pairing and the configured output mode are maintained.

2. Understanding the ZBRRA output behaviour

The ZBRRA is a programmable receiver in the Harmony XB5R (plastic) and XB4R (metal) wireless and battery less pushbutton range. It converts radio frames from ZBRT* wireless batteryless transmitters into dry contact outputs. Its two outputs are electromechanical changeover relays, so their unpowered position is a mechanical rest position, not a saved state.

3. Contact state according to receiver condition

Receiver condition	NC contact (11-12 / 21-22)	NO contact (12-14 / 22-24)	Relay state
Not powered (supply off or lost)	Closed	Open	De-energized - default state
Powered, no command received	Closed	Open	De-energized
Powered, output ON in monostable mode	Open	Closed	Energized while the command is active
Powered, output ON in bistable or stop/start mode	Open	Closed	Energized until the next command
Supply lost while the output is ON	Closed	Open	De-energized - the ON state is not maintained
Supply restored	Closed	Open	De-energized until a new command is received

4. Related references

Function	Reference	Description
Programmable receiver	ZBRRA	2 changeover relay outputs 3 A, 24-240 V AC/DC, monostable / bistable / stop-start, 6 indicating LEDs
Transmitter	ZBRT1	Wireless and batteryless transmitter, without head
Transmitter head, plastic	ZB5RTA2	ZB5R plastic pushbutton head, black cap, spring return
Transmitter head, metal	ZB4RTA2	ZB4R metal pushbutton head, black cap, spring return
Visual feedback	ZBRV1	Visual feedback module for ZBRT transmitters
Antenna	ZBRA1	Relay antenna to extend radio range

Download the instruction sheet from the product page on se.com, browse the current wireless offer in DigiCat, or contact Schneider Electric technical support to validate a layout before installation.

Julkaistu: Schneider Electric Suomi