Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 90)

Publication AG-UM008C-EN-P - February 2005
3-22 Configuring MicroLogix 1100/1200/1500 Controllers
Configuring a Slave Station To choose the processor as a slave station, follow the steps below
using your programming software:
Reply Message Wait
Timeout Defines the amount of time, in 20 millisecond increments, that the master station will wait after
receiving an ACK (to a master-initiated message) before polling the slave station for a reply.
Choose a time that is, at minimum, equal to the longest time that a slave station needs to
format a reply packet. This would typically be the maximum scan time of the slave station.
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 the processor retries the message or the
message errors out. This timeout value is also used for the poll response timeout. See page
3-14 for recommendations to minimize this value.
RTS Off Delay Defines the amount of time, in 20 millisecond increments, that elapses between the end of the
message transmission and the de-assertion of the RTS signal. This time delay is a buffer to
make sure that the modem has transmitted the message but should normally be left at zero. See
page 3-11 for further guidelines for setting this parameter.
RTS Send Delay Defines the amount of time, in 20 millisecond increments, that elapses between the assertion
of the RTS signal and the beginning of the message transmission. This time allows the modem
to prepare to transmit the message. The Clear-to-Send (CTS) signal must be high for
transmission to occur. See page 3-11 for further guidelines for setting this parameter.
Pre-Transmit Delay Defines the amount of time, in 1 millisecond increments, that elapses between when the
processor has a message to send and when it asserts the RTS signal.
Message Retries Defines the number of times a master station retries a message before it declares the message
undeliverable.
Table 3.4 Configuring a MicroLogix 1100/1200/1500 as a Master Using Message-based Communication Mode
Parameter Selections
1. To bring up the Channel
Configuration interface,
double-click on the Channel
Configuration icon.