Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 311)

Publication AG-UM008C-EN-P - February 2005
Configuring RSLinx Classic Software for DF1 Half-Duplex Communications 9-5
Figure 9.4 DF1 Protocol Settings
Table 9.4 DF1 Protocol Settings Parameter Descriptions
Control Control Text
Qty Retries When polling and transmitting, this controls how many attempts are made before giving up on that
operation. Zero (0) is not a legal value. The default is 3 retries.
ACK and Poll Pkt Timeout
(ms) Timeout value before the driver assumes that the current operation has failed. After failure, if the retry
count has not been exceeded, the driver attempts it again. The default is 3000 ms.
Min Poll Delay After Xmit'g
Pkt (ms) After the driver transmits a packet to a slave device, this is the minimum time it waits before polling the
slave for responses. This is useful when there is a high overhead associated with connecting to the slave
device (such as going through a dial-up modem), and you want a reply to a packet sent to the slave while
still connected to it. Default is zero (0).
Max Pkt Wait Time (s) Maximum period of time the driver keeps a packet buffered in memory while it is waiting for an
opportunity to be transmitted to the slave. When this period is exceeded, the packet times out. The default
is 150 seconds.
Max Retransmission Wait
Time (s) Similar to Max Pkt Wait Time, except that Max Retransmission Wait Time applies to packets sent from
one slave device to another slave device (where the driver acts as a forwarder of messages). The default is
600 seconds.
Error Checking Mode Select BCC or CRC. All devices on the network must be configured the same. The default is BCC.
Detect and Ignore Duplicate
Messages If selected, the driver keeps the header information of the last packet received from each slave device in
memory. If a new packet is identical to the last packet, it is considered a duplicate, so the slave is ACKed
and the packet is discarded. The default is checked.
Execute Received Diagnostic
Commands Diagnostic command packets addressed to the same station address as the master are executed and reply
packets are sent to the sender. If the checkbox is cleared, an error message is returned to the sender. The
default is checked.
Defaults Resets the default values for each control on the dialog box.