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Rockwell Automation GMLC Reference Manual User Manual

Page 740

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Publication GMLC-5.2 - November 1999

Using Block Transfers

703

Program Listing Report

PLC-5/30

Rung 2:0

EXAMPLE OF SENDING DATA TO THE MOTION CONTROLLER

| BLOCK

BLOCK

|

| TRANSFER

S CLASS

TRANSFER

|

| SEND DATA

BTW

BTR

PROGRAM

WRITE

|

| CONDITION

ENABLE

ENABLE RUNNING

CONTROL

|

|

I:002

N10:0

N10:5

I:011

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

|

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

+-(EN)-+

|

00

15

15

10

|Rack

01|

|

|

|Group

0+-(DN) |

|

|Module

0|

|

|

|Control Block

N10:0+-(ER) |

|

|Data file

N13:0|

|

|

|Length

0|

|

|

|Continuous

N|

|

|

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

|

Other interlocks in the BTW rung can be required for your application. At
a minimum, you should have all of the following:

A condition that causes the BTW (don’t send a BTW on every PLC
scan).

The enable bits (Bit 15 of the BT control block) of all other block
transfers in the ladder.

The block transfer length should always be set to zero, as shown in the
ladder above. This causes all 64 words of the data file to be sent. In
addition, continuous block transfers should not be used.

Using the enable bits from each block transfer to interlock all other block
transfers ensures that the block transfers always occur in the order in
which they appear in the PLC ladder. This is the same technique used to
interlock other RIO devices.