Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 44)

Publication AG-UM008C-EN-P - February 2005
2-6 Configuring Enhanced PLC-5 Processors
Options Station Address Define the octal address of the processor on the DF1 half-duplex link. Each station on a link
must have a unique address. Choose an address between 0 and 376
8
.
Station address 377
8
is the broadcast address, which you cannot select as a station’s
individual address.
DF1 Retries Defines the number of times a master station retries either a message before the master
station declares the message undeliverable, or poll packet to an active station before the
master station declares that station to now be inactive.
RTS Send Delay RTS send delay is 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.
RTS Off Delay RTS off delay is 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.
ACK Timeout Define the amount of time, in 20 millisecond increments, that you want the processor to wait
for an acknowledgment from a slave station to its transmitted message before the processor
retries the message or the message errors out.
Reply Message
Wait Define 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 is typically the maximum scan time of the slave station.
Note: This field is only valid if the polling mode field is configured to be MESSAGE BASED.
MSG Application
Timeout Define the number of 30 second increments within which the reply message must be received
before the error bit is set on the message. The timer starts when the ACK is received.
Polling Polling Mode If you want to receive:
•
only one message from a slave station per its turn, choose STANDARD (SINGLE
MESSAGE TRANSFER PER NODE SCAN).
Choose this method only if it is critical to keep the poll list scan time to a minimum.
•
as many messages from a slave station as it has, choose STANDARD (MULTIPLE
MESSAGE TRANSFER PER NODE SCAN).
Master Message
Transmit If you want the master station to:
•
send all of the master station-initiated MSG instructions to the slave stations before
polling the next slave station in the poll list, choose Between Station Polls.
This method makes certain that master station-initiated messages are sent in a timely
and regular manner (after every slave station poll).
•
only send master station-initiated MSG instructions when the master’s station number
appears in the polling sequence, choose In Poll Sequence.
With this method, sending master station-initiated messages are dependent upon
where and how often the master station appears in the poll list. To achieve the same
goal as the Between Station Polls method, the master-station’s address would have to
appear after every slave-station’s address.
RSLogix 5 Tab Parameter Selections