Campbell Scientific LR4 Four Channel Latching Relay Module - Manual (Page 10)

LR4 Four Channel Latching Relay Module
6. LED Indicators
Five LEDs are on the control module. The main status LED indicates a
successful power up by turning on for one second. Rapid flashing for
approximately 3 seconds indicates a power-up problem. When the status LED
is on, any of the contacts that are in the 1 state will also have its LED on.
In normal operation, the status LED briefly flashes once every 5 seconds. Any
contact in the 1 state will have its LED flash with the status LED. A brief
button press can be used to activate the LEDs for a longer period of time to
observe the relay states. The button press must be less than 1 second to avoid
toggling any of the relays.
7. Using SDI-12
Contemporary dataloggers that support the SDI-12 protocol are the CR200X-
series, CR800, CR850, CR1000, CR3000, and CR5000. Retired dataloggers
that support the SDI-12 protocol include the CR200-series, CR510, CR10(X),
and CR23X.
7.1 SDI-12 Wiring
When the LR4 is controlled via the SDI-12 protocol, the RX/B terminal is not
connected. Often, the DIG I/O terminal is also not connected. The state of the
DIG I/O terminal can be read using SDI-12; it is meant to handle some custom
applications (contact Campbell Scientific for more information).
For SDI-12 communications, the CABLE3CBL three-conductor cable is
recommended to connect the LR4 to the datalogger when the DIG I/O port is
not used. The CABLE4CBL four-conductor cable is recommended when
using the DIG I/O port. Table 1 shows the datalogger connections.
Power-off the system before wiring the LR4. CAUTION
TABLE 1. SDI-12 Wiring
LR4 Terminals Function Datalogger Terminal
GND Power ground and
shield G
POWER Positive dc power
source (9-30 Vdc) 12V
SDI-12 /TX/A SDI-12 signal Cx (control port) 1
RX /B Not used Not used
DIG. I/O (optional) Readable digital input Cx (control port) 2
1 Where x is the control port number. Use the dedicated SDI-12 port on
CR5000 datalogger.
2
Where x is the control port number. Use of DIG I/O is for some custom
applications. Contact Campbell Scientific for more information.
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