USER MANUAL Manual

Remote I/O Communications 8–17
Publication 2706-6.1
In the Message/Variable/Slave run mode you can:
• trigger single messages through a PLC using the Remote I/O port
• send variables to be included in a message
• insert ASCII input data into a message
• return ASCII input data to a PLC
• return the message number of the message being run to a PLC
• send Real Time Clock or date data to a PLC
• place messages on Historical Events Stack
• require handshaking between DL40 Plus and PLC
• override slave address selected as a message attribute with an
address sent with the message trigger
Triggering Messages through a PLC
You can trigger a single message by either discrete I/O or a Block
Transfer Write. For details see pages 8–20 to 8–23.
Sending Variables to be Included in Message
Your PLC can include variables with the message trigger. Up to the
equivalent of 6 full word variables can be sent if using Discrete I/O
(depending on rack size) or up to the equivalent of 10 full word
variables can be sent using a Block Transfer Write (independent of
rack size).
Variable types include:
• 16 bit binary (1 variable per word)
• 8 bit ASCII (2 per word)
• 4 digit signed Binary Coded Decimal (BCD) (1 per word)
• 1 digit (4 bit) unsigned BCD (4 per word)
You can send variables via an RS-232/RS-485 link or the DL40 Plus
Keyboard Port. See Chapter 6, Serial Port Communications, for
more information.
Message/Variable/Slave
Run Mode