Trane Mobrus RTU TR1 Series, Instruction Manual

6

The Modbus RTU interface to the TR1 Series
VFD requires drive parameter values selected
as shown. See the 

TR1 Series VFD Installation

and Operation Manual 

for details on selecting

and changing parameter values, if necessary.

Drive

Parameter

Settings for

Modbus RTU

Communica-

tion

• Parameter 500, 

Protocol

:  Modbus RTU

• Parameter 501, 

Address

:  001 - 247

• Parameter 502, 

Baud Rate

:  300 - 9600

baud. (Factory default is 9600 baud.)

• Parameter 570, 

Modbus Parity/Frame

:

select from the following, based on
application.

Even Parity/1 Stop

Odd Parity/1 Stop

No Parilty/1 Stop (factory default)

• Parameter 571, 

Modbus Communication

Timeout

: 10 - 2000 ms. (Factory default

setting is 100 ms.)

Network

Connection

EIA-485 Connector

RTxD' (-)

RTxD (+)

COM

69

68

61

Pin 1

Connect the Modbus RTU control wiring to
drive terminals (+)68  and (-)69 on control card
as illustrated.

Use 18 - 24 AWG (1.5 mm) shielded, twisted
pair control wiring. Tighten to 4.5 in-lbs (0.5
Nm).

Shielded wiring must be used. Ground shield
to drive terminal 61, drive casing, or as
appropriate for the network application.

DIP switches 2 and 3, located on the main
control board of the drive directly above the
EIA-485 connector, can be used to terminate
drives on the Modbus network (see figure). In
addition to serial communication, switch 4 is
used to isolate a low voltage, external DC
power supply. The factory default switch
positions are ON (see table).

Drive DIP

Switch

Settings for

Network

Connection

Drive DIP Switches

SWITCH

SETTING

Switch 1 

No function 

Switches 2 & 3 

Used for terminating an EIA-485 interface. When 

the drive is the first, last, or only device on a 

network, switches 2 and 3 must be ON. 
When the drive is in any other location on the 

network, switches 2 and 3 must be OFF. 

Switch 4 

Separates the common potential of the internal 24 

VDC supply from the common potential of external 

24 VDC supply. When switch 4 is in the OFF 

position, the external 24 VDC supply is isolated 

from the drive. See the drive operation manual for 

more information on switch 4. 

Drive DIP Switche Settings