Rockwell Automation 1747-KE,D17476.12 DH-485/RS-232C Interface Module - Manual (Page 79)

Publication 1747-UM005B-EN-P - March 2006
Module Configuration Using the Backplane 6-13
DH-485 Port Setup Parameters
Build the Modem Init String
Configuration Packets When the module is powered up for the first time, the Modem Init
String is empty. You can build the string using the two Data ID
numbers reserved for the Modem Init String.
The packet with Data ID 4 will set up the first 14 characters of the
Modem Init String. If you require less than 14 characters, place a NULL
in the location immediately following the last valid character. The
module ignores all characters beyond the NULL value. If you require
exactly 14 characters, the module automatically places a NULL after
the 14th character.
If you need more than 14 characters, you also need to send the packet
with Data ID 5. Send this packet only after you send the packet with
Data ID 4. Here again you need to place a NULL immediately
following the last valid character. If you use all available characters of
the string, a NULL is automatically placed after the 28th character.
Parameter Default Options Description
Node Address 2 0...31 (decimal) The address of this node on the DH-485 network. Every
device on the DH-485 network must be given a unique node
address. For optimum performance, set devices to
consecutive addresses starting at 0. This minimizes the
solicitation of new stations.
Max. Node Address 31 1...31 (decimal) The number of nodes that will be polled. For optimum
performance this value should be set no larger than the
value of the highest numbered node on the network.
Message Timeout 10,000 ms 100...12,750 ms The time to wait for a response to a message sent on a
DH-485 network.
Pass Through Disabled 0=Disabled,
1=Enabled Determines whether diagnostic commands are executed by
the module (Disabled) or passed through to the host
(Enabled).
Communication Rate 19200 0=300, 1=600,
2=1200, 3=2400,
4=4800, 5=9600,
6 and 7=19200 The speed in bits per second at which data is transferred
on the DH-485 link.
Important: All stations on the DH-485 link must be set to
the same communication rate.