13
VLT is a registered Danfoss trade mark
MG.10.P2.22
Status LEDs
The Modbus RTU option card has two LEDs.
One LED is used as a status for Modbus
communications and the other as a status for
VLT drive communications. Both LEDs use the
same communications patterns. On power up,
each LED state is flashed on for 250
milliseconds (Red, Green, Orange, Off). The
VLT LED powers up first, then the Modbus
LED. After power up, the following are the only
valid states:
• Flashing Green (1 Hz): Communications
online (VLT LED) or receiving data (Modbus
LED)
• Flashing Red (1 Hz): Communications time
out
• Solid Red: Major fault, communications
halted
Option Card
Operability
Loop Back
Test
A loop back test to confirm Modbus RTU option
card operability can be performed. The option
card must be removed from the adjustable
frequency drive to gain access to the 8-input
dip switch for baud rate and parity and to
rewire the option card connectors.
Ensure that power has been
removed from adjustable fre-
quency drive for a minimum of 14
minutes for 220 and 500 V units
and 30 minutes for 550-600 V units
to allow voltage to dissipate.
• Remove the option card in accordance
with the procedures described in the
installation section of this manual.
• Set the dip switch positions in accordance
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
ON
ON
ON
OFF
OFF
ON
ON
ON
DANGER
!
with the table below.
• Remove all wiring from both the 6-pin
option card connector and the 3-pin
RS-485 connector.
• Wire the 6-pin option card connector to
the 3-pin RS-485 connector as described
below.
• Apply power to the unit.
After the normal status LED check at
power-up (see Status LEDs), the loop back
test sets both LEDs to orange for a successful
test and red if the test fails.
6-Pin Connector
RS-485 Connector
Pin 2
to
Pin 3
to
Pin 4
to
Pin 3
Pin 2
Pin 1
Loop Back Test Switch Positions
VLT LED
Modbus LED
