Rockwell Automation 1793-OE2S FLEX INTEGRA ANALOG MOD - Manual (Page 23)

Publication 1793-6.5.1 - April 1999
Chapter
3
Module Programming
Chapter Objectives In this chapter, we tell you about:
• analog data format
• block transfer programming
• sample programs for the PLC-3 and PLC-5 processors
Block Transfer
Programming Your module communicates with the processor through bidirectional block
transfers. This is the sequential operation of both read and write block
transfer instructions.
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
scaling, alarms, 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.
The following sample programs are minimum programs; all rungs and
conditioning must be included in your application program. You can disable
BTRs, or add interlocks to prevent writes if desired. Do not eliminate any
storage bits or interlocks included in the sample programs. If interlocks are
removed, the program may not work properly.
Your program should monitor status bits, block transfer read and block
transfer write activity.
ATTENTION: If the analog module is not powered up
before the remote I/O adapter, the adapter will not recognize
the module. Make certain that the analog module is installed
and powered before or simultaneously with the remote I/O
adapter. If the adapter does not establish communication with
the module, cycle power to the adapter.