Rockwell Automation GMLC Reference Manual - Manual (Page 739)

Publication GMLC-5.2 - November 1999
702 Using the RIO Adapter Option
Using Block Transfers
Block transfers are used to transfer user variable, data parameter, data bit,
and cam table values between a data file in the PLC and the motion
controller. A block transfer write (BTW) sends data from the PLC to the
motion controller, while a block transfer read (BTR) gets data from the
motion controller and stores it in the PLC. Up to 60 consecutive user
variable or cam table values can be sent or gotten in each block transfer
depending on the specified data format.
As long as the block transfers are not interlocked with the motion
controller’s program running bit in the PLC ladder, a program need not be
running in the motion controller for block transfers to work properly. In
fact, it is often easier to verify RIO operation using the GML
Commander’s online interface—selecting the RIO Adapter tag, or using
General Watch—to directly examine the variable values once they have
been updated by the block transfer.
Sending Data to the Motion Controller
A block transfer write (BTW) is used to send data from the PLC to the
motion controller. For example, the PLC rung below executes a block
transfer write that sends the data in PLC data file N13 to the motion
controller when a switch (I:002/00) is closed.
!
ATTENTION: The interlocks shown for the BTW are the
minimum required for reliable operation. Other conditions
can be required in your program.