Rockwell-automation 1771-QB Linear Pos. Manual de usuario descargar pdf (Pagina 62)

Chapter

61

Interpreting ModuletoPLC Data (READS)

This chapter explains how to monitor module operation from a programmable

controller by reading and interpreting status block data that the module transfers

to the programmable controller’s data tables.

You must program the programmable controller to communicate with the Linear

Positioning Module through block read and block write instructions. The data

blocks are:

status block

parameter block

setpoint block

motion block

command block

The block read instruction transfers the status block data from the module to the

programmable controller data table. The block write instruction transfers the

parameter block, the setpoint block, the motion block and the command block

data from the programmable controller data table to the module. This chapter

tells you how to interpret the status block data. Chapter 7 tells you how to

format the parameter block, the setpoint block, and the command block data.

Chapter 9 explains the motion block.

The status block contains information on the status of each axis. Until the

module receives a parameter block, the status block consists of five words (i.e.

the default assumption of one axis). The size of subsequent status blocks

depends on the configuration you program through the parameter block.

Number of Axes Status Block Length

1 5 words - default

2 9 words - default

1 or 2 up to 33 words depending on

block transfer length requested

You can set the block transfer read instruction to include extended status

information by specifying a block transfer length of 33. If you specify a length

of 0 (or 64), the module returns the default: 5 words for one axis and 9 for two.

PLC Communication Overview

Status Block

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Rockwell-automation 1771-QB Linear Pos. Manual de usuario Pagina 62