Rockwell Automation GMLC Reference Manual - Manual (Page 745)

Publication GMLC-5.2 - November 1999
708 Using the RIO Adapter Option
Constructing the PLC Data File
A BTW data file must be constructed in the PLC, regardless whether the
PLC is sending data to or getting data from the motion controller. This
data file specifies the type of data (variable, data parameter, etc.), the
specific data item (which variable, which data parameter, etc.), or the first
item if transferring multiple user variables or cam table values, the
number of items, and the format of the values to be read or written. The
first three words of the data file are used for this information.
If the PLC is sending data to the motion controller, the remainder of the
data file contains the values of the specified items, and the last word is the
end-of-block delimiter (000D hex). If the PLC is getting data from the
motion controller, no data values need be specified and so the end-of-
block delimiter is word 3. Note that the end-of-block delimiter is always
the last word used in the data file, which is not necessarily the last
possible word in the data file.
Up to 60 sequential user variables or cam table points can be transferred
in a single block transfer, depending on the numeric format specified for
the transfer. In addition, multiple non-sequential user variables, system
variables, data parameters, or data bit values can be transferred in a single
block transfer using the intermediate delimiter (003A hex) to concatenate
multiple individual transfers into a single BTW. Construct the BTW data
file in the PLC as shown below:
RIO Adapter Block Transfer Write Data File Format
Word Description
0 Data Type: 7B at (hex) to send data;
7D at (hex) to read data
where:
a is the Axis (0 - 4, 8, or 9),
t is the Data Type:
0 = User Variable
1 = Data Parameter
2 = Data Bit
3 = Master Cam Table Position Point
4 = Master Cam Table Time Point
5 = Slave Cam Table Position Point
6 = System Variable (read data only)