Rockwell Automation 1747-KE,D17476.12 DH-485/RS-232C Interface Module - Manual (Page 36)

Publication 1747-UM005B-EN-P - March 2006
3-10 Communicate with the Interface Module
Slave-to-slave communication
Communicate with DH-485
Devices
DH-485 Token Passing Devices
The interface module operates as a token passing master on the
DH-485 network. It can communicate with other DH-485 master
stations (such as an SLC 5/02 processor) and with DH-485 token
passing slave devices (such as an SLC 5/01 processor).
The module communicates with other master stations using the
Allen-Bradley programmable controller command set. For details,
refer to the DF1 Protocol and Command Set Reference Manual,
publication 1770-RM516.
When the interface module is in Slave-to-slave communication occurs
Local mode Only if the module’s DF1 node is the same as the
DH-485 node for which the message is destined.
In this mode the RSLinx computer can only
communicate with one SLC node.
For example, if you want a DF1 slave terminal in
the illustration above to communicate with an
SLC processor in node 2 of the DH-485 network,
then the interface module’s DF1 slave address
must be set to 2.
Remote mode Between the DF1 slave and any of the DH-485
devices connected to the interface module. The
addresses for the DH-485 devices are
determined by the group number in the interface
module.
Refer to the Half-duplex Remote Address
Conversion Table in Chapter 3.
For example, if the interface module in the
illustration above is configured as group 03, and
the DH-485 node to be accessed has a DH-485
address of 01, then the DF1 slave device will use
address 141 (octal) when accessing this device.
ATTENTION
Do not force outputs to a remote SLC system through
the interface module. Phone line disturbances,
interface module failure, or other system failure
could disrupt remote communications and cause the
outputs to remain active.