USER MANUAL Manual

Remote I/O Communications 8–13
Publication 2706-6.1
With the Remote I/O version of the DL40 Plus, messages are
normally triggered from a PLC connected to the DL40 Plus.
However, messages can also be triggered via the Keyboard port, the
RS-485 port or the RS-232 port.
DIP Switch 2-4 enables or disables Block Transfers.
• Discrete I/O (Block Transfers disabled)
– Block Transfers are ignored
– amount of data sent/returned depends on rack size
• Block Transfer enabled
– data in Discrete I/O image tables ignored
– amount of data sent/returned independent of rack size
Triggering the Same Message Consecutively
To avoid retriggering of a message via the I/O scan, the DL40 Plus
looks for changes to the message number in the Output Image or
Block Transfer Write to trigger messages. To trigger the same
message twice in a row, you must:
• trigger the message the first time.
• trigger a message with a Message Number of 0.
• trigger the original message a second time.
Note: In Message/Variable/Slave run mode, changing the slave
address also retriggers the same message.
Triggering Messages