Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 102)

Publication AG-UM008C-EN-P - February 2005
3-34 Configuring MicroLogix 1100/1200/1500 Controllers
Define the communication parameters shown in Table 3.9 when
configuring a MicroLogix 1100/1200/1500 controller for DF1
full-duplex communication.
Table 3.9 Configuring a MicroLogix 1100/1200/1500 controller for DF1 Full-Duplex Communication
Parameter Selections
Baud Rate Select a communication rate that all devices in your system support. Configure all
devices in the system for the same communication rate.
Parity Parity provides additional message packet error detection. To implement even parity
checking, choose Even. To implement no parity checking, choose None.
Source ID This is the address, in decimal, that is used as the source address in any message
initiated by this controller.
Control Line This parameter defines the mode in which the driver operates. Choose a method
appropriate for your system’s configuration:
•
If you are not using a modem, choose NO HANDSHAKING.
•
If you are using full-duplex modems, choose FULL-DUPLEX MODEM (RTS
ON).
See page 3-8 for descriptions of the control line operation settings.
Error Detection With this selection, you choose how the controller 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 controller 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 Detect lets the controller 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 controller 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 controller 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 controller to send after an ACK
timeout occurs.