LR4 (4-Channel Latching-Relay Module)
The LR4 relay module is useful in situations where the power is unreliable or where power needs to be conserved, because it does not need electricity to keep the relay closed. The state of the relay can only be changed by sending a command to the LR4 or by manually toggling the relay button.
Unlike traditional relays that must be continuously powered to keep their state, the LR4 mechanically latches the relay’s state, allowing power to be removed. The only way to change the state of a relay is to send a command to the LR4 or to press the manual toggle button. The data logger sends commands to the LR4 via the SDI-12 protocol or ModBus protocol.
|Function||Used in situations with unreliable power or where power needs to be conserved.|
|Number of Channels||4|
|Supply Voltage||9 to 30 Vdc|
|Operating Voltage||12 Vdc nominal (9 to 30 Vdc)|
|Operating Temperature||-40° to +60°C|
|Maximum Voltage Ratings of Relays||30 Vdc/30 Vac|
|Dimensions||17.0 x 3.7 x 6.1 cm (6.7 x 1.5 x 2.4 in.)|
|Weight||0.48 kg (1.05 lb)|
|Quiescent||< 2.0 mA|
|Peak||< 250 mA|
|Hardware||SDI-12, RS-232, RS-485|
|Protocol||SDI-12 Version 1.3, or ModBus via RS-232/RS-485 at 19,200 bps|
Digital I/O Input Voltage
|Relay #1, Relay #2||Two independent; single pole single throw (SPST)|
|Relay #3, Relay #4||Two independent; single pole double throw (SPDT)|
|Relay #1, Relay #2||Not to exceed 100 VA or 5 A|
|Relay #3, Relay #4||Not to exceed 60 VA or 2 A|
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.