Getting data from the motion controller – Rockwell Automation GMLC Reference Manual User Manual

Page 742

Publication GMLC-5.2 - November 1999

Using Block Transfers

705

Getting Data from the Motion Controller

A block transfer write (BTW), followed immediately by a block transfer
read (BTR), is used to get (read) data from the motion controller. The
BTW specifies the data to be read; the BTR reads the current values and
stores them in a data file in the PLC. Every BTR must be preceded with a
BTW to set up the values to be read.

For example, the PLC rungs below execute a BTW to request the data
specified in PLC data file N14 from the motion controller, and a BTR to
read the data from the motion controller and store it in PLC data file N7
when a switch (I:002/01) is closed. The specified data is read
continuously while the switch is closed.

Program Listing Report

PLC-5/30

Rung 2:0
EXAMPLE OF GETTING DATA FROM THE MOTION CONTROLLER.
| BLOCK

BLOCK

| TRANSFER

S CLASS

TRANSFER

| GET DATA

BTW

BTR

PROGRAM

WRITE

| CONDITION

ENABLE

RUNNING

CONTROL

I:002

N10:0

N10:5

I:011

+BTW-----------------+

+----] [------]/[-------]/[-------] [------+BLOCK TRNSFR WRITE

+-(EN)-+

|Rack

01|

|Group

0+-(DN) |

|Module

|Control Block

N10:0+-(ER) |

|Data file

N14:0|

|Length

|Continuous

+--------------------+

Rung 2:1
ONCE THE BTW HAS REQUESTED THE DATA, A BTR IS PERFORMED TO READ IT.
| BLOCK