Hardware Installation
Modbus Address
Before the R9120-5 transceiver can be used, you must set the Modbus address of the R9120-5
transceiver This address must be unique among all Modbus devices in the system, including all devices
that are connected on remote wireless links Address 0 (all switches OFF) is not allowed
Select an address, and set the dipswitches to match
The sum of the value of the switches is the address In the example to the right, address 52 is set by
placing switch 4, 16 and 32 to the ON position
OTEE:
N
4 + 16 + 32 = 52
System Settings
For most systems, set all of the system switches to the OFF position
Radio channel
: This option selects the channel number that can be used to isolate a group of
ModHoppers This option may be set for channels 0 to 6 Channel 7 (all 3 switches ON) is not allowed
Programming
: Set the
Prog Enable
to OFF for normal operation
485 Termination Enable
: Set the
485 Term En
to ON to enable a 120 Ohm termination resistor on the
RS485 network This should be used when the R9120-5 transceiver is on the end of a 485 wiring run
Set this switch to OFF when the R9120-5 transceiver is in the middle of an RS485 wiring run
Port RS232 or RS485
: Set the switch to the OFF position for RS485 operation The R9120-5
transceiver can communicate via the RS232 connection however most Modbus devices will need
485 terminals
Baud Rate
: This option sets the serial port speed for the Modbus devices connected to the R9120-5
transceiver Set this option to OFF for 19200 Set the switch to ON for 9600 baud
Reserved
: Set this option to OFF
Status LEDs
The device should power up and be ready in a few seconds The LEDs should blink in the following manner
• The Alive LED starts to blink about once per second
• The Alarm LED will blink when transmission errors occur
• The RF TX/RX LEDs will blink when the radio is receiving or transmitting data
• The RS485 LEDs will blink for local Modbus activity
• The Pulse input LEDs will light when the corresponding pulse input terminals are closed
• If the device has the -SN option, the 400 MHz LED will blink when an RF packet from a 400 MHz sensor
transmitter is received
Signal Strength Test
When the R9120-5 transceiver is operating, the
Test
button can be used to report the signal strength received by the R9120-5
transceiver from another unit
Press and hold down the
Test
button The status LEDs will light up as a bar graph display Each LED is approximately 10% of
scale For example, if PULSE 1 and 2 are on, the received strength is approximately 20% to 29%
For useful signal reporting, it is important to turn OFF all but one other R9120-5 transceiver When reporting the signal
strength, the most recent wireless transmission received is displayed If two R9120-5 transceivers are transmitting, the display
will only show the most recently received packet, and you will not be able to determine which R9120-5 transceiver the signal
strength being reported
OTEE:
N
The normal operation of the R9120-5 transceiver is suspended while the
Test
button is pressed Modbus
communications and wireless transmissions are not processed
Page 6
June 2016
XMT-UM-02107-EN-01