RLE LD5200 V.2.3 - Manual (Page 85)

rletech.com LD5200 User Guide 85
C
H A P T E R
C HAPTER 0
M
ODBUS
C
OMMUNICATION
5.1 Comm Port Settings
The Modbus/EIA-485 Configuration Menu allows users to configure all three of the LD5200’s
EIA-485 Modbus ports. The LD5200 is configurable as a both a Modbus master and a Modbus
slave device. As a slave device, the LD5200 can have only one master. All three ports may
have their addresses and baud rates set in this menu. All addresses may be different and can be
configured from 0 (disabled) to 254. Baud rates can be different and can be configured as 9600
(default), 19200, or 38400. Settings can be configured through both the LCD and the web
interface.
The Leak Detection Master option enables slave units to activate the LD5200 when they are
triggered into an alarm state. This function is beneficial when the LD5200 is a remote system
that does not have personnel in the immediate vicinity to monitor the alarm status.
When using the leak detection master option, the LD5200 relays can be activated according to
the slave unit alarm. If the slave has a leak alarm or a cable break alarm, the LD5200 leak or
cable relay will change state, respectively (i.e. it will trigger that an alarm is present). The zone
will then appear on the LCD and an alarm state will be reported to the top level of the system.
5.2 Leak Detection Modbus Master
This feature allows the LD5200 to act as a Modbus master, so it can talk to other RLE distance
read panels. The system status can be viewed by using the view zones menu. The LD5200 will
display leak, cable break, cable contamination, and loss of communications alarms from the
slave units connected to it.
5.2.1 Connect Distance Read Panels to the LD5200
Using a two wire configuration, connect the slave units in a 485 daisy chain. You will have to
set the EIA-485 slave address in each Leak detection unit. The first unit connected must be set
to address 2. The following units will increase in numeric order by one unit (e.g., the next unit
would be set to address 3, the following would be set to address 4, etc.; see Figure 5.1.)