Rockwell Automation 2706-LV2P_LV2R_LV4P_LV4R DL40 PLUS USER MANUAL - Manual (Page 106)

Remote I/O Communications 8–14
Publication 2706-6.1
The DL40 Plus returns two types of data to a PLC:
•
ASCII Input data
•
Clock/Date data
ASCII Input Data
The DL40 Plus returns ASCII Input data during the PLCs I/O scan as
part of the Input Image Table or Block Transfer Read Data Table.
This happens automatically unless you request that Clock/Date data
be returned. You can only input ASCII Input Data using the
Keyboard port. This data is cleared after one scan or read.
Clock/Date Data
Two ways to request that the DL40 Plus return Clock/Date data are:
•
Set Always Send Clock Data to yes.
Note: Always Send Clock Data is a parameter of the Triggering
Port Setup for Remote I/O.
•
Trigger special message 912 or 12 (time) or 913 or 13 (date).
The PLC must internally keep track of which special message was
triggered to determine if time or date data is being returned.
The DL40 Plus continues to return Time/Date data as a response to
special message 912 or 913:
•
for 100 milliseconds if Hardware handshaking is not set
or
•
until the DL40 Plus receives acknowledgement that the PLC has
received the data if Hardware handshaking is set.
Whenever Clock/Date data is being returned to the PLC, the
Clock/Date data bit in the Input Image Table is set.
Returning Data to the PLC