Allen-Bradley PLC-5 User Manual page 164

10-14 Communicating with Devices on a Serial Link
This field Specifies
RTS off-delay The time delay between the time the
end of the message transmission and
the RTS is de-asserted
This time delay is a buffer to make
sure that the modem has transmitted
the message.
ACK timeout The amount of time you want the
controller to wait for an
acknowledgment from a remote
station to its transmitted message
before the controller retries the
message or the message errors out
Reply msg wait The amount of time the master will
wait after receiving an ACK (to a
master-initiated message) before
polling the slave for a reply
MSG application The number of seconds within which
timeout the reply message must be received
before the error bit is set on the
message
The timer starts when the ladder
program first initiates the message
and is restarted if/when the ACK is
received.
Polling Settings
Polling mode The current value of the polling mode Select one of the following:
Publication 1785-UM012D-EN-P - July 2005
Configure by Doing the Following
Enter a value 0-255. Limits are defined in 20 ms intervals. For example
to wait 40 ms, type 2. The recommended time elapse is 0, unless you are
using a modem that automatically returns the CTS as soon as it receives
the RTS. If this is the case, enter a delay time to make sure the modem is
able to transmit before it attempts to send the message.
Enter a value 0-65535. Limits are defined in 20 ms intervals. For example
to wait 40 ms, type 2. The recommended time elapse is 1 second.
Specify 1 second by typing 50.
Only define this if you are message-based mode. Enter a valid value
0-65535 (in 20ms increments).
Select one of the following:
1:30-60 seconds
2:60-90 seconds
3:90-120 seconds
4:120-150 seconds
5:150-180 seconds
6:180-210 seconds
7:210-240 seconds
MESSAGE BASED (ALLOW SLAVE TO INITIATE MESSAGES)—default—
this option allows remote station initiated messages to be processed
after all master-initiated messages
MESSAGE BASED (DO NOT ALLOW SLAVE TO INITIATE MESSAGES)—
remote station-initiated messages will be acknowledged but not
processed
STANDARD (MULTIPLE MESSAGE TRANSFER PER NODE SCAN)—the
master polls stations based on a list; each station can transmit multiple
messages per node scan
STANDARD (SINGLE MESSAGE TRANSFER PER NODE SCAN)—the
master polls stations based on a list; each station can transmit only one
message per node scan