Bradley Smoker PLC-5 user manual Polling Settings

10-14Communicating with Devices on a Serial Link

This field Specifies Configure by Doing the Following

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.

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.

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

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.

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

Only define this if you are message-based mode. Enter a valid value 0-65535 (in 20ms increments).

MSG application	The number of seconds within which	Select one of the following:
timeout	the reply message must be received
	before the error bit is set on the	1:30-60 seconds
	message	2:60-90 seconds
	The timer starts when the ladder
	program first initiates the message	3:90-120 seconds
	and is restarted if/when the ACK is
	received.	4:120-150 seconds
		5:150-180 seconds
		6:180-210 seconds
		7:210-240 seconds
Polling Settings
Polling mode	The current value of the polling mode	Select one of the following:
		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

Publication 1785-UM012D-EN-P - July 2005