Rockwell Automation 1747-KE,D17476.12 DH-485/RS-232C Interface Module - Manual (Page 65)

Publication 1747-UM005B-EN-P - March 2006
Module Configuration Using an ASCII Terminal 5-11
DF1 Half-duplex Setup Parameters
Parameter Default Options Description
Duplicate Packet
Detection Disabled Enabled, Disabled Determines whether duplicate message detection is Disabled
or Enabled. When enabled, duplicate messages will be
acknowledged and discarded.
Checksum BCC BCC, CRC16 Determines the type of error detection that will be used on
the DF1 link. It must be the same as that for the DF1 device.
Constant Carrier Detect Disabled Disabled, Enabled If enabled, hardware handshaking is forced on. The module
will monitor the carrier from the modem (DCD signal) and will
not begin communication until it is detected.
Modem Init String (blank) Lets you configure your modem using Hayes commands upon
every power cycle of the module. For example, entering ATDT
here would get the modem’s attention (AT) and set it to tone
dialing (DT). Sending a (~) character will produce a one
second wait on the modem. Refer to your modem user
manual for details.
Modem Init String Delay 0 s 0...25 s Determines the amount of time the module will wait before
sending the Modem Init String to the modem.
Message Timeout 10,000 ms 100...12,750 ms The time to wait for a response to a message sent on a DF1
network. This parameter is rounded down to the nearest 50
ms increment. For example, if you enter 199 ms, it is
accepted as 150 ms.
Hardware Handshaking Disabled Disabled, Enabled If enabled, the module will use the RTS and CTS signals for
control of the modem.
Poll Timeout 200 x 5 ms (0...65,535) x 5 ms Determines the time to wait to be polled by the DF1 master
before a transmission request is ignored.
Message Retries 2 0...254 Determines the number of allowable retries on the DF1 link
before failure.
RTS On Delay 0 x 5 ms (0...65,535) x 5 ms Determines the delay between the RTS (Request to Send)
signal and the start of transmission by the module. This
parameter is only required when communicating with the
type of radio modem that requires a delay after exerting the
RTS signal. It only takes effect if hardware handshaking is
enabled. Refer to your modem user manual.
RTS Off Delay 0 x 5 ms (0...65,499) x 5 ms Determines the delay between the end of the message and
the module setting RTS (Request to Send) inactive. This
parameter is only required when communicating with
modems that require a delay between sending the last
character and raising the RTS signal. It only takes effect if
hardware handshaking is enabled. Refer to your modem user
manual.
Local/Remote Mode Local Local, Remote Refer to pages 3-3 and 3-4 for a description of these
half-duplex modes.
Slave Address/
Group Number 0 Slave Add. = 0...254
Group No. = 0...7 Slave address is a half-duplex local mode parameter and is
the address of the module on the DF1 link. Group Number is a
half-duplex remote mode parameter and allows a means of
addressing more than 32 DH-485 nodes.
This is explained in detail on page 3-4.
Master Station Address 8 (10 octal) 0...254 (decimal) Determines the address of the half-duplex DF1 master
device. For slave-to-slave communication, this is the address
of the DF1 slave device. Refer to page 3-10.