Service Monitor User Manual
Danfoss Turbocor Compressors Inc.
3
ECD-00007M Rev. 1
3
Getting Started
3.1
Cable Connection
The monitoring program communicates with the
compressor via the Modbus* protocol using either the
RS232 or RS485 connection at the Chiller Interface
module. RS485 communication requires an RS485/RS232
adapter (user-supplied). RS232 communication is
recommended for cable lengths not exceeding 15 meters
(50 feet) between the PC and compressor. For cables that
run up to 100 meters (328 feet), use the RS485
communication line. Always use shielded, twisted-pair
cable for data communications
*The Modbus protocol was originally developed to exchange information
between products on the factory floor. This protocol has become a de facto
standard for exchanging data and control between PLC systems. Modbus is
a registered trademark of Modicon Corp.
3.1.1 RS232 Connection
1.
Connect one end of the RS232 cable (user-supplied) to
the DB9 connector on the Chiller Interface module; see
Figure 1.
2.
Connect the other end of the cable to an available COM
port on the PC.
3.
Confirm that jumpers JP2 and JP7 are in proper
positions before starting.
JP2 is the Modbus termination jumper. Install the
jumper if the Modbus connection is at the end of a
cable run.
Remove JP7 to enable RS-232 communication with the
PC.
3.1.2 RS485 Connection
1.
Connect the RS485/RS232 adapter directly onto the PC
COM port.
Connect the other side of the adapter to the Modbus. Figure
2 shows the PC and adapter connections to the Modbus for
a single compressor application. Ensure that the termination
jumper (JP2) on the Chiller Interface module is installed.
Figure 3 shows the PC and adapter connections to the
Modbus for a multiple compressor application. In this case,
set the termination jumper only on the Chiller Interface
module that is connected at the end of the Modbus cable
run.
Figure 1 RS232 Connector - Chiller Interface
Module