Rockwell Automation 1203 Serial Communications Module Series A - Manual (Page 35)

4 Chapter
4-1
SCANport Datalink Operation
Chapter Objectives In this chapter, you will read about:
S Configuring the SCANport device Datalinks.
S Datalink Operation.
SCANport Datalinks A Datalink is a type of pointer used by some SCANport devices to transfer
information to the drive. Datalinks allow parameter values to be written
when the Logic Command and Reference are sent to the drive. Datalinks
also allow parameter values to be read whenever the Logic Status and
Feedback are read.
SCANport devices that support this function have a group of parameters
for Datalink configuration. These parameters are identified as “Datalink
In” and “Datalink Out” parameters. The Datalink functions are enabled by
setting the correct switch to “Enable” on SW3 of the Communications
Module and configuring the “Datalink In” and “Datalink Out” parameters
in the SCANport device.
Each Datalink consists of two 16-bit words of input and two 16-bit words
of output. Each of the two input words can be configured to write to a
different destination parameter inside the SCANport device by setting the
two “Datalink In” parameters for that Datalink to the desired destination
parameters. Similarly, each of the two output words is configured by
setting the two “Datalink Out” parameters for that Datalink.
Each Datalink switch on SW3 can enable or disable one Datalink. If a
Datalink is enabled the value of the parameters set into the “Datalink Out”
parameters will be transferred to the Communications Module and the data
sent by the Communications Module for the Datalink will be transferred
into the parameters set into the “Datalink In” parameters. If a Datalink is
not enabled the data transferred to the SCANport device for that Datalink
will be zero and any data sent by the SCANport device will be ignored by
the Communications Module.
If no “Datalink In” parameter is configured for an input word that word
will be ignored. If no “Datalink Out” parameter is configured for an output
word the output word will be undefined (usually set to zero).