Manual

Communicating with Your Module

Chapter 3

3-10

BlockTransfer Read

You can generate all block-transfer reads from your 1771-TCM module

thru a single block-transfer read instruction. Enter the block length as 64

words. Write your ladder logic so that when you receive a block of data in

the 64-word block addressed by the block-transfer read instruction, you

first read the block identification code at the beginning of the block and

then based on the ID, send the block of data to the appropriate address for

that particular type of block

System Satus Block

64 words

Calibration Read Block

14 words

64word block

addressed by the

blocktransfer

read instruction

Gains Block

57 words

1771TCM ModulePLC Data Table

Blocktransfer Read

Step

2 

You read the block ID from

the data in the 64word bloc

addressed by the BTW

instruction, and based on the

ID, send the block of data to

the appropriate address for

that particular type of block.

Step

1 

You first use the

BTR instruction to

bring the block of

data from the

module.

In the dynamic block that you send to the module, you specify whether the

module should send back a gains block or a system status block in

subsequent block-transfer reads.