Elettronica Santerno SINUS K, User Manual

Page: 101 / 191

SINUS K
INSTALLATION
INSTRUCTIONS
101/ 191
The basic wiring recommended from MODBUS-IDA association for the connection of 2-wire devices is as
follows:
Figure 46: Recommended wiring diagram for “2-wire” MODBUS wiring.
Note that the network composed of the termination resistor and the polarization resistors is integrated into the
inverter and can be activated via appropriate dip-switches. Figure 46 shows the termination network in the
devices at both ends of the chain. The terminator must be activated in those devices only.
NOTE
Four-pair data transfer cables of Category 5 are normally used for serial links.
Although their usage is not recommended, cables of Category 5 can be used for
short cable paths. Note that the colours of such cables are different from the colours
defined by MODBUS-IDA association. One pair is used for D1/D0 signals, one pair
is used as a “Common” conductor, while the remaining two pairs must not be
connected to any other device, or must be connected to the “Common”.
NOTE
All devices connected to the communication multidrop network should be grounded
to the same conductor to minimize any difference of ground potentials between
devices that can affect communication.
NOTE
The common terminal for the supply of the inverter control board is isolated from
grounding. If one or multiple inverters are connected to a communication device with
a grounded common (typically a computer), a low-impedance path between control
boards and grounding occurs. High-frequency disturbance could come from the
inverter power components and interfere with the communication device operation.
If this happens, provide the communication device with a galvanically isolated
interface, type RS485/RS232.