HP Anab EQ5 - Manual (Page 118)

EQ5 AC Drive Operations Manual
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TECO – Westinghouse Motor Company Serial Communications Modbus 112
8-4 RS-485 Modbus RTU Serial Communications
The serial communications interface supports operation, configuration and monitoring of inverter
functions through an EIA/RS-485 connection. The serial interface is based on Modbus RTU
protocol. This protocol allows the inverter to function as an RTU slave on an industrial network.
8- 4-1 Transmission Specifications
Item Specification
Physical level EIA/RS-485
Transmission distance 1600 ft (500 m)
Number of nodes 32 total
Transmission speed 19200, 9600, 4800, 2400 [bits/s]
Transmission mode Half duplex
Transmission protocol Modbus RTU
Character code Binary
Character length 8 bits
Error check CRC
8- 4-2 Connection
Connection method:
Use shielded wire and connect to the control terminals (DX-, DX+ and SD). A terminating
resistor should be added between the data lines on the each end of the network. The value of
the terminating resistor depends on the characteristic impedance of the cable. A common
value is 120 ohms.
Control terminals:
Terminal
Designation
Terminal Name Function Description
DX+ RS-485 communication data (+) Input/output terminals for RS-485
communication.
DX- RS-485 communication data (–)
SD Cable shield Electrically floating
8- 4-3 Serial Interface Configuration
Inverter function codes H30 to H39 are used to configure the serial interface parameters, such
as device address, baud rate and error response.
8- 4- 4 Modbus RTU Functions
The following RTU functions are supported. The maximum number of consecutive parameters
for function 03 and 16 messages is 16.
Code Description
03 Read Holding Registers (16 registers maximum)
06 Preset Single Register
16 Preset Multiple Registers (16 registers maximum)