Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 173)

Publication AG-UM008C-EN-P - February 2005
Configuring SLC 5/03, 5/04, and 5/05 Processors 4-35
DF1 Full-Duplex Channel Status
Channel Status data is stored in the diagnostic file defined on the
Channel 0 Configuration screen. Table 4.10 on page 4-36 explains
information regarding the diagnostic counter data displayed.
Chan. 0 System Error Detection With this selection, you choose how the processor checks the accuracy of each DF1
packet transmission.
BCC: This algorithm provides a medium level of data security. It cannot detect:
•
transposition of bytes during transmission of a packet
•
the insertion or deletion of data values of zero within a packet
CRC: This algorithm provides a higher level of data security.
Select an error detection method that all devices in your configuration can use.
When possible, choose CRC.
Embedded Responses To use embedded responses, choose Enabled. If you want the processor to use
embedded responses only when it detects embedded responses from another
device, choose Auto-detect.
If you are communicating with another Allen-Bradley device, choose Enabled.
Embedded responses increase network traffic efficiency.
Duplicate Packet Detect Duplicate Packet Detect lets the SLC detect if it has received a message that is a
duplicate of its most recent message from the master station. If you choose
duplicate detect, the processor will acknowledge (ACK) the message but will not act
on it since it has already performed the message’s task when it received the
command from the first message.
If you want to detect duplicate packets and discard them, check this parameter. If
you want to accept duplicate packets and execute them, leave this parameter
unchecked.
ACK Timeout The amount of time, in 20 millisecond increments, that you want the processor to
wait for an acknowledgment to the message it has sent before sending an enquiry
(ENQ) for the reply.
NAK Retries The number of times the processor will resend a message packet because the
processor received a NAK response to the previous message packet transmission.
ENQ Retries The number of enquiries (ENQs) that you want the processor to send after an ACK
timeout occurs.
Table 4.9 Configure an SLC 5/03, 5/04, or 5/05 Processor for DF1 Full-Duplex Communication
Tab Parameter Selections
1. Double-click on the Channel
Status Icon Located beneath
the Configuration icon to bring
up the Channel Status screen.