Rockwell Automation 1797-IRT8 FLEX Ex Thermocouple/RTD/mV Input Module User Manual - Manual (Page 75)

1 Publication 1797-6.5.2 - February 2001
Appendix
B
Programming the FLEX Ex I/O Modules
Using RIO
What this Chapter Contains Read this appendix to program the 1797-IRT8 thermocouple/RTD/mV
input module.
Enter Block Transfer
Instructions The FLEX Ex thermocouple/RTD/mV modules communicate 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
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.