Publication 1794-6.5.12 - November 1997
Chapter
3
Programming Your
Thermocouple/RTD Input
Module
What This Chapter
Contains
To initiate communication between the Thermocouple/RTD input module
and your PLC processor, you must enter block transfer instructions into
your ladder logic program. Use this chapter to enter the necessary block
transfer instructions into your ladder logic program.
Enter Block Transfer
Instructions
The Thermocouple/RTD input module communicates with the PLC
processor through bidirectional block transfers. This is the sequential
operation of both read and write block transfer instructions.
Before you configure the module, you need to enter block transfer
instructions into your ladder logic. The following example programs
illustrate the minimum programming required for communication to take
place between the module and a PLC processor. These programs can be
modified to suit your application requirements.
A configuration block transfer write (BTW) is initiated when the analog
module is first powered up, and subsequently only when the programmer
wants to enable or disable features of the module. The configuration BTW
sets the bits which enable the programmable features of the module, such
as filters and signal ranges, etc. Block transfer reads are performed to
retrieve information from the module.
Block transfer read (BTR) programming moves status and data from the
module to the processor’s data table. The processor user program initiates
the request to transfer data from the module to the processor. The
transferred words contain module status, channel status and input data
from the module.
Your program should monitor status bits, block transfer read and block
transfer write activity.
To edit your ladder logic you
See page
Enter Block Transfer Instructions. . . . . . . . . . . . . . . . . . . . . . . . 3-1
PLC-2 Family Processors . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
PLC-3 Family Processors . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
PLC-5 Family Processors . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
PLC-5/250 Processors . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Содержание 1794-IRT8
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