ProSoft Technology 5201-DFNT-DH485 - Manual (Page 15)

Functional Overview DH485 ♦ ProLinx Gateway
Driver Manual DH485 Interface
ProSoft Technology, Inc.
Page 15 of 44
August 27, 2009
2.3 Protocol Functional Specifications
2.3.1 Functional Specifications - DH-485
The DH-485 protocol in its native form is a peer to peer token passing network.
The ProLinx DH-485 driver accesses the network functioning either as a Master
or as a Slave.
General Protocol Information
Error Checking
BCC and CRC
Communication Parameters Local Station ID: 0 to 31
Port 0 Baud Rate: 110 to 38.4K baud
Port 1 Baud Rate: 110 to 19200 baud
Stop Bits: 1 or 2
Data Size: 7 or 8 bits
Parity: None, Even, Odd
RTS Timing delays: 0 to 65535 milliseconds
DH-485 Slave Mode
In Slave mode, the module accepts commands from one or more Masters to
read/write data stored in the module’s internal data memory. In this mode, the
ProLinx unit is answering DH-485 commands and has the appearance of an SLC
processor to the network.
DH-485 Master Mode
In Master mode, the ProLinx DH-485 driver will actively gather data from other
devices on the network, controlling the read/write data transfer between the
gateway and other DH-485 devices, such as SLC processors. Data transfer can
be initiated and executed with the other devices without any ladder logic being
required in the Rockwell Automation slave hardware.
DH485 Functioning as a Master
Command List
Up to 100 command per master port, each fully
configurable for function, slave address, register to/from
addressing and word/bit count
Polling of command list User configurable polling of commands, including
disabled, continuous and on change of data (write only)
2.3.2 General Specifications
ProLinx ® Communication Gateways provide connectivity for two or more
dissimilar network types. The gateways, encased in sturdy extruded aluminum,
are stand-alone DIN-rail mounted solutions that provide data transfer between
many of today’s most widely used industrial automation protocols.