Power supply from cab - SmartRelay 3 system
This connection option requires the fewest free lines in the trailing cable and avoids voltage drops due to excessively long lines. The controller can be installed outside the lift where it is protected in a place, such as the engineering room.
The reader is not powered via the controller. Instead, it is connected to the existing power supply in the lift cab, which provides electricity for lighting, doors and other elements. The voltage may need to be converted with a power supply unit, so that it is within the specified voltage range for the SmartOutput module and reader (see Properties). The voltages supplied to the individual components do not need to be identical. It is thus possible to operate the controller with 12 V while the reader in the lift is operated with 24 V.
Common earth connection
In this specific case, four lines are also needed to supply power to the cab.
Line | Use |
|---|---|
1 | Controller – reader: Data line A |
2 | Controller – reader: Data line B |
3 | Controller – SmartOutput module: Data line A |
4 | Controller – SmartOutput module: Data line B |
DANGER
Electric shock due to mains voltage
An electric shock may be caused when connecting the non-hazardous earth (low voltage) to a conductor which carries the mains voltage.
- Only use conductors with a low-voltage potential (< 42 V) as a common earth cable!
- Protect live cables, so people do not touch them accidentally!
NOTE
A common earth connection is required between the controller, reader and SmartOutput modules. The cab power supply earth connection can be used to save on lines in the trailing cable. The controller's earth connection needs to be connected to the cab power supply earth connection in this case.
See Common earth with power supply on wiring.
Separate earth connection
If a common earth cable cannot be used for the cab power supply and the components, an additional line needs to be assigned in the trailing cable. In this specific case, five lines are also needed to supply power to the cab.
Line | Use |
|---|---|
1 | Earth connection between controller, reader and SmartOutput modules |
2 | Controller – reader: Data line A |
3 | Controller – reader: Data line B |
4 | Controller – SmartOutput module: Data line A |
5 | Controller – SmartOutput module: Data line B |
The earth cables in the power supplies are separated from the common earth cable in this case.
See Common earth with SREL3 components and Connecting one or more readers on wiring.